Nonblood Specimens and Tests PDF

CHAPTER 13 Nonblood Specimens and Tests KEY TERMS Help learn these terms with WORKBOOK Matching Exercise 13-1. OBJECTIVES Upon successful completion of this chapter, the reader should be able to: AFP gastric analysis serous ﬂuid amniotic ﬂuid H. pylori sputum buccal swab iontophoresis suprapubic C&S midstream sweat chloride C. difﬁcile NP synovial ﬂuid catheterized O&P 24-hour urine clean catch occult blood UA CSF pericardial ﬂuid UTI expectorate peritoneal ﬂuid FOBT pleural ﬂuid 1 Deﬁne the key terms and abbreviations listed at the beginning of the chapter. 2 Describe nonblood specimen labeling and handling. 3 Name and describe the various urine tests, specimen types, and collection and handling methods. 4 Identify and describe the types of nonblood specimens other than urine and explain why these specimens are tested. 5 Describe collection and handling procedures for nonblood specimens other than urine. 6 Identify tests performed on various nonblood specimens other than urine. 436 UNIT IV: SPECIAL PROCEDURES Overview Although blood is the specimen of choice for many laboratory tests, various other body substances are also analyzed. The phlebotomist may be involved in obtaining the specimens (e.g., throat swab collection), test administration (e.g., sweat chloride collection), instruction (e.g., urine collection), processing (accessioning and preparing the specimen for testing), or merely labeling or transporting the specimens to the lab. This chapter addresses routine and special nonblood specimens and procedures, including the collection and handling of urine specimens and other nonblood body ﬂuids and substances. A phlebotomist with a thorough understanding of all aspects of nonblood specimen collection helps ensure the quality of the specimens and the accuracy of test results. Nonblood Specimen Labeling and Handling Proper labeling helps avoid testing delays, which can compromise patient care. Nonblood specimens should be labeled with the same identifying information as blood specimens. In addition, since many body fuids are similar in appearance, labeling should include the type and/or source of the specimen. Because the lid is removed for testing, the label should be applied to the container, not the lid, so as to avoid misidentiﬁcation. Follow facility protocol. KEY POINT Phlebotomists are often asked to transport specimens to the lab that have been collected by other healthcare personnel. It is important for the phlebotomist to verify proper labeling before accepting a specimen for transport. Nonblood specimens have various handling requirements. The phlebotomist must be familiar with these requirements to protect the integrity of the specimen and help ensure accurate test results. In addition, all body substances are potentially infectious, and standard precautions must be observed in handling them. Nonblood Body-Fluid Specimens Nonblood body ﬂuids are liquid or semiliquid substances produced by the body and found in the intracellular and interstitial spaces and within various organs (e.g., the bladder) and body spaces (e.g., joints). URINE Urine, which has been studied since the very beginning of laboratory medicine, is the most frequently analyzed nonblood body ﬂuid. It is readily available, easy to collect, and generally inexpensive to test; its analysis can provide information on many of the body’s major metabolic functions. Analysis of urine can aid in monitoring wellness, the diagnosis and treatment of urinary tract infections, the detection and monitoring of metabolic disease, and determining the effectiveness or complications of therapy. Accurate results depend on collection method, container used, specimen transportation and handling, and timeliness of testing. CAUTION: If urine specimens are not tested promptly, urine components can change. For example, cellular elements decompose, bilirubin breaks down to biliverdin, and bacteria multiply, leading to erroneous test results. Inpatient urine specimen collection is typically handled by nursing personnel. Outpatient urine specimen collection is often handled by phlebotomists. The phlebotomist must be able to explain urine collection procedures without embarrassing the patient. CHAPTER 13: NONBLOOD SPECIMENS AND TESTS 437 KEY POINT Verbal urine specimen collection instructions must be accompanied by written instructions, preferably with illustrations. In outpatient areas, written instructions are often posted on the wall in the restroom designated for patient urine collections. The type of specimen preferred for many urine tests is the ﬁrst urine voided (passed naturally from the bladder or urinated) in the morning, because it is the most concentrated. However, the type of urine specimen and method of collection vary depending on the type of test. The most common urine tests, types of specimens, and collection methods follow. Common Urine Tests Watch the Routine Urinalysis video at http:// thepoint.lww.com/ McCall5e. Routine Urinalysis (UA) A routine urinalysis (UA) is the most commonly requested urine test because it screens for urinary and systemic disorders. It may be ordered as part of a physical examination or at various times during hospitalization. A routine UA typically includes physical, chemical, and microscopic analysis of the urine specimen. Physical analysis involves macroscopic observation and notation of color, clarity, and odor, as well as measurements of volume and speciﬁc gravity (SG) or osmolality. (SG and osmolality indicate urine concentration.) Physical analysis can also help explain or conﬁrm chemical and microscopic results. Chemical analysis can detect bacteria, bilirubin, blood (red blood cells and hemoglobin), glucose, ketones, leukocytes, nitrite, protein, and urobilinogen, and measure pH and speciﬁc gravity. Analysis is commonly performed using a plastic reagent strip (often called a dipstick) that contains pads impregnated with test reagents. Each test has its own pad. The strip is dipped into the urine and color reactions that take place on the pads are compared to a color chart, which is usually found on the label of the reagent strip container. Special timing, which is not the same for all tests, is involved in reading the results, which are reported in the manner indicated on the color chart. Results are typically reported using the terms trace, 1⫹, 2⫹, and so on to indicate the degree of a positive result, and negative (neg) or (⫺) when no reaction is noted. Machines are available that read the strips automatically. The strip is used once and then discarded. Microscopic analysis identiﬁes urine components such as cells, crystals, and microorganisms by examining a sample of urine sediment under a microscope. To obtain the sediment, a measured portion of urine is centrifuged in a special plastic tube. After centrifugation, the supernatant, or top portion of the specimen, is discarded. A drop of the remaining sediment is placed either on a glass slide and covered with a small square of glass called a coverslip or placed in a special chamber. It is then examined under the microscope by a laboratory technologist or technician. There are also machines that perform this function. A random specimen is acceptable for routine urinalysis. However, to avoid contamination of the specimen by genital secretions, pubic hair, and bacteria surrounding the urinary opening, the ideal procedure for collecting a specimen for routine urinalysis is referred to as midstream collection. (See “Urine Collection Methods,” for regular voided and midstream collection methods). Routine UA specimens should be collected in clear, dry, chemically clean containers with tight-ﬁtting lids. If a culture and sensitivity (C&S) is also ordered on the specimen, the container should be sterile. Urine specimens should be transported to the lab promptly. Specimens that cannot be transported or analyzed promptly can be held at room temperature and protected from light for up to 2 hours. Specimens held longer should be refrigerated. Specimens that require both UA and C&S testing should be refrigerated if immediate processing is not possible. (Urinalysis is also discussed under “Point of Care Testing” in Chapter 11.) Urine Culture and Sensitivity A urine culture and sensitivity (C&S) test may be requested on a patient with symptoms of urinary tract infection (UTI). The culture involves placing a measured portion of urine on a 438 UNIT IV: SPECIAL PROCEDURES Figure 13-1 Urine specimens collected in sterile containers for C&S testing. special nutrient medium that encourages the growth of microorganisms, incubating it for 18 to 24 hours, checking it for growth, and identifying any microorganisms that grow. If a microorganism is identiﬁed, a sensitivity or antibiotic susceptibility test is performed to determine which antibiotics will be effective against the microorganism. Urine for C&S testing must be collected in a sterile container (Fig. 13-1), following midstream clean-catch (see “Urine Collection Methods”) procedures to ensure that the specimen is free of contaminating matter from the external genital areas. CAUTION: Specimens for C&S and other microbiologic studies should be transported to the lab and processed immediately. If a delay in transportation or processing is unavoidable, the specimen should be refrigerated. Urine Cytology Studies Cytology studies on urine are performed to detect cancer, cytomegalovirus, and other viral and inﬂammatory diseases of the bladder and other structures of the urinary system. Cells from the lining of the urinary tract are readily shed into the urine, and a smear containing them can easily be prepared from urinary sediment or ﬁltrate. The smear is stained by the Papanicolaou (PAP) method and examined under a microscope for the presence of abnormal cells. A fresh clean-catch specimen is required for the test. Ideally, the specimen should be examined as soon after collection as possible. If a delay is unavoidable, the specimen can be preserved by the addition of an equal volume of 50% alcohol. Follow facility protocol. Urine Drug Screening Urine drug screening is performed to detect illicit use of recreational drugs, use of anabolic steroids to enhance performance in sports, and unwarranted use of prescription drugs; it is also used to monitor therapeutic drug use in order to minimize withdrawal symptoms and to conﬁrm a diagnosis of drug overdose. With the exception of alcohol, urine is preferred for drug screening, since many drugs can be detected in urine but not blood. Screening tests are typically performed in groups based on drug classiﬁcations or families (see Chapter 11, Table 11-2). A random sample in a chemically clean, covered container is required for the test. Specimens containing blood cells or having a high or low urine pH (highly alkaline or highly acid) or a low speciﬁc gravity will yield erroneous results and will require recollection of the specimen. (For additional information, see “Forensic Specimens” in Chapter 11.) CHAPTER 13: NONBLOOD SPECIMENS AND TESTS 439 Urine Glucose and Ketone Testing Urine reagent test strips are also used to screen for diabetes and monitor glucose and ketone levels in diabetics. The body breaks down carbohydrates to supply itself with glucose. Ketones are created when the body breaks down fat for energy because the diet is deﬁcient in carbohydrates or when the body does not metabolize glucose properly. The testing of urine ketone levels can be used to diagnose diabetic ketoacidosis and help differentiate between diabetic and nondiabetic coma. Results are read by comparing color changes on the test strip to a color chart. Urine Pregnancy Testing Pregnancy can be conﬁrmed by testing urine for the presence of human chorionic gonadotropin (HCG), a hormone produced by cells within the developing placenta, that appears in serum and urine approximately 8 to 10 days after conception, or fertilization. Although a random urine specimen can be used for testing, the ﬁrst morning specimen is preferred because it is typically more concentrated and would therefore have the highest HCG concentration. HCG also appears in the urine of patients with melanoma, tumors of the ovaries or testes, and certain types of cancer, including breast, lung, and kidney. Other Urine Tests Numerous chemistry tests—including electrophoresis, tests for heavy metals (e.g., copper and lead), myoglobin clearance, creatinine clearance, and porphyrins—can be performed on urine specimens. Many of these tests require a pooled timed specimen, such as a 24-hour collection. Types of Urine Specimens Random Random urine specimens can be collected at any time. They are used primarily for routine urinalysis and screening tests. Random refers only to the timing of the specimen and not the method of collection. First Morning/8-Hour Specimen A ﬁrst morning or 8-hour urine specimen (also called a ﬁrst voided, overnight, or early morning specimen) is usually collected immediately upon awakening in the morning after approximately 8 hours of sleep. This type of specimen normally has a higher speciﬁc gravity, which means that it is more concentrated than a random specimen. For this reason, ﬁrst morning specimens are often requested to conﬁrm results of random specimens and specimens with low speciﬁc gravity. Fasting A fasting specimen is typically used for glucose monitoring. It differs from a ﬁrst morning specimen in that the specimen is the second specimen voided after a period of fasting. This helps assure that the specimen will not be affected by food consumed prior to fasting. Timed Some tests require individual urine specimens collected at speciﬁc times. Others require the collection and pooling of urine throughout a speciﬁc time period. Some of the most frequently encountered timed urine tests are as follows. Tolerance Test Specimen. Tolerance tests typically require collection of urine at speciﬁc times. The traditional standard glucose tolerance test (GTT) requires individual urine specimens collected serially at speciﬁc times that correspond with the timing of blood collection, such as fasting, 1/2 hour, 1 hour, and so on. Timing of the specimens is important in the interpretation of test results. For this reason, the specimens must be collected as close to the requested time 440 UNIT IV: SPECIAL PROCEDURES Figure 13-2 Two styles of 24-hour urine specimen collection containers. as possible, and the label of the specimen should include the time of collection and the type of specimen (e.g., fasting, 1/2 hour). 2-Hour Postprandial Specimen. A 2-hour postprandial (PP) specimen is collected 2 hours after a meal and tested for glucose. It is primarily used to monitor the insulin therapy of patients with diabetes mellitus. The patient is instructed to void shortly before consuming a normal meal and to collect a specimen 2 hours later. Results are often compared with glucose results on fasting urine and fasting blood specimens. Test your knowledge of 24-hour urine collection with WORKBOOK Skills Drill 13-3. 24-Hour Specimen. A 24-hour urine specimen is collected to allow quantitative analysis of a urine analyte. Collection and pooling of all urine voided in the 24-hour period is critical. The best time to begin a 24-hour collection is when the patient wakes in the morning, typically between 6 and 8 A.M. Collection of the specimen requires a large, clean, preferably wide-mouth container capable of holding several liters (Fig. 13-2). A special collection device that ﬁts over the toilet and looks somewhat like an upside-down hat is sometimes provided to the patient to make collection of the specimen easier. Some 24-hour specimens require the addition of a preservative prior to collection. Others, such as creatinine clearance, must be kept refrigerated throughout the collection period. Information on proper handling of the specimen can be obtained by consulting the laboratory procedure manual. The label of the specimen, in addition to standard patient identiﬁcation, must state that the specimen is a 24-hour specimen, the type of preservative added to the container (if applicable), and any precautions associated with it, as some preservatives can burn the skin. The procedure for 24-hour urine collection is shown in Procedure 13-1. KEY POINT A urine creatinine clearance test also requires collection of a blood creatinine specimen, which is ideally collected at the midpoint of urine collection (i.e., 12 hours into urine collection). Double-Voided Specimen. A double-voided urine specimen is one that requires emptying the bladder and then waiting a speciﬁed amount of time (typically 30 minutes) before collecting the specimen. It is most commonly used to test urine for glucose and ketones. A fresh double-voided specimen is thought to more accurately reﬂect the blood concentration of the analyte tested, whereas a specimen that has been held in the bladder for an extended period may not. CHAPTER 13: NONBLOOD SPECIMENS AND TESTS 441 PROCEDURE 13-1 24-Hour Urine Collection Procedure PURPOSE: To provide instruction in how to properly collect a 24-hour urine specimen EQUIPMENT: Requisition, specimen label, 24-hour urine container, preservative (if applicable), disposable ice chest (if required), copy of written instructions Step Explanation/Rationale 1. Void into toilet as usual upon awakening. The bladder must be empty when timing starts. Urine voided is from the previous time period. 2. Note the time and date on the specimen label, place it on the container, and begin timing. Timing (which should ideally start between 6 and 8 A.M.) is important. If urine is collected for a longer or shorter period, results will be inaccurate. The label should be afﬁxed to the container, not the lid. 3. Collect all urine voided for the next 24 hours. Results are based on the total amount of urine produced in 24 hours. 4. Refrigerate the specimen throughout the collection period if required. Most specimens (except urate tests) require refrigeration to maintain analyte integrity. The specimen container should be kept cool in a disposable ice chest, placed in the bath tub, for example. 5. When a bowel movement is anticipated, collect the urine specimen before, not after it. Prevents fecal contamination of the specimen. 6. Drink a normal amount of ﬂuid unless instructed to do otherwise. Prevents dehydration and facilitates specimen collection. 7. Void one last time at the end of the 24 hours. This specimen must be added to the container. 8. Seal the container, place it in a portable cooler, and transport it to the laboratory ASAP. Cooling and prompt delivery help protect the integrity of the specimen. Urine Collection Methods Regular Voided Specimen A regular voided urine collection requires no special patient preparation and is collected by having the patient void (urinate) into a clean urine container. Midstream Specimen A midstream urine collection is performed to obtain a specimen that is free of genital secretions, pubic hair, and bacteria surrounding the urinary opening. To collect a midstream specimen, the patient voids the initial urine ﬂow into the toilet. The urine ﬂow is interrupted momentarily and then restarted, at which time a sufﬁcient amount of urine is collected into a specimen container. The last of the urine ﬂow is voided into the toilet. Check out WORKBOOK Knowledge Drill 13-3 to see if you know the rationale behind each step in the clean-catch procedure. Midstream Clean-Catch Specimen Midstream clean-catch urine is collected in a sterile container and yields a specimen that is suitable for microbial analysis or culture and sensitivity testing. Clean-catch procedures are necessary to ensure that the specimen is free of contaminating matter from the external genital areas. Special cleaning of the genital area is required before the specimen is collected. The cleaning methods vary somewhat depending upon whether the patient is male or female. A phlebotomist must be able to explain the proper procedure to both male and female patients. The clean-catch urine collection procedure for females is described in Procedure 13-2. The procedure for males is described in Procedure 13-3. 442 UNIT IV: SPECIAL PROCEDURES PROCEDURE 13-2 Clean-Catch Urine Collection Procedure for Women PURPOSE: To instruct a female in how to properly collect a clean-catch urine specimen EQUIPMENT: Requisition, specimen label, sterile urine container, special sterile antiseptic wipes, and copy of written instructions Step Rationale 1. Wash hands thoroughly. Aids in infection control and helps avoid contamination of the site while cleaning. 2. Remove the lid of the container, being careful not to touch the inside of the cover or the container. The lid and container must remain sterile for accurate interpretation of results. 3. Stand in a squatting position over the toilet. Facilitates cleaning and downward ﬂow of urine. 4. Separate the folds of skin around the urinary opening. Allows proper cleaning of the area. 5. Cleanse the area on either side and around the opening with the special wipes, using a fresh wipe for each area and wiping from front to back. Discard used wipes in the trash. Antiseptic solution in the wipe removes bacteria from area. Front-to-back motion carries bacteria away from the site. 6. While keeping the skin folds separated, void into the toilet for a few seconds. Separation of the folds maintains site antisepsis. Voiding the ﬁrst portion of urine into the toilet washes away the antiseptic and microbes remaining in the urinary opening. 7. Touching only the outside and without letting it touch the genital area, bring the urine container into the urine stream until a sufﬁcient amount of urine (30–100 mL) is collected. Bringing the urine container into the stream without touching the genital area helps ensure sterility of the specimen. An adequate amount of urine is needed to perform the test. 8. Void the remaining urine into the toilet. Only 30–100 mL of urine is needed for the test. 9. Cover the specimen with the lid provided, touching only the outside surfaces of the lid and container. The lid and container must remain sterile, and the specimen must be covered to maintain sterility and protect others from exposure to the contents. 10. Clean any urine off the outside of the container with an antiseptic wipe. Aids in infection control. 11. Wash hands. Aids in infection control. 12. Hand specimen to phlebotomist or place where instructed if already labeled. Follow facility protocol. Catheterized Specimen A catheterized urine specimen is collected from a sterile catheter inserted through the urethra into the bladder. A catheterized specimen is collected when a patient is having trouble voiding or is already catheterized for other reasons. Catheterized specimens are sometimes collected on babies to obtain a specimen for C&S, on female patients to prevent vaginal contamination of the specimen, and on bedridden patients when serial specimen collections are needed. Suprapubic Aspiration Suprapubic collection of urine involves inserting a needle directly into the urinary bladder and aspirating (withdrawing by suction) the urine directly from the bladder into a sterile syringe. CHAPTER 13: NONBLOOD SPECIMENS AND TESTS 443 PROCEDURE 13-3 Clean-Catch Urine Collection Procedure for Men PURPOSE: To instruct a male in how to properly collect a clean-catch urine specimen EQUIPMENT: Requisition, specimen label, sterile urine container, special sterile antiseptic wipes, and copy of written instructions Step Rationale 1. Wash hands thoroughly. Aids in infection control and helps avoid contamination of the site while cleaning. 2. Remove the lid of the container, being careful not to touch the inside of the cover or the container. The lid and container must remain sterile for accurate interpretation of results. 3. Wash the end of the penis with the special wipe (or soapy water), beginning at the urethral opening and working away from it in a circular motion (the foreskin of an uncircumcised male must ﬁrst be retracted). Repeat the procedure with a clean wipe. The foreskin must be retracted to allow thorough cleaning of the penis. Antiseptic solution in the wipe removes bacteria from the area. Wiping away from the urinary opening carries microbes away from the site. 4. Keeping the foreskin retracted, if applicable, void into the toilet for a few seconds. Keeping the foreskin retracted maintains site antisepsis. Voiding the ﬁrst portion of urine into the toilet washes away the antiseptic and microbes remaining in the urinary opening. 5. Touching only the outside and without letting it touch the penis, bring the urine container into the urine stream until a sufﬁcient amount of urine (30–100 mL) is collected. Bringing the urine container into the stream without touching the penis helps ensure sterility of the specimen. An adequate amount of urine is needed to perform the test. 6. Void the remaining urine into the toilet. Only 30–100 mL of urine is needed for the test. 7. Cover the specimen with the lid provided, touching only the outside surfaces of the lid and container. The lid and container must remain sterile, and the specimen must be covered to maintain sterility specimen must be covered to maintain sterility and protect others from exposure to the contents. 8. Clean any urine spilled on the outside of the container with an antiseptic wipe. Aids in infection control. 9. Wash hands. Aids in infection control. 10. Hand specimen to phlebotomist or place where instructed if already labeled. Follow facility protocol. The specimen is then transferred into a sterile urine container or tube. The procedure normally requires the use of local anesthesia and is performed by a physician. If the patient has a catheter, the specimen can be collected from the catheter by a nurse using a sterile needle and syringe. Suprapubic aspiration is used for samples for microbial analysis or cytology studies. It is sometimes used to obtain uncontaminated samples from infants and young children. Pediatric Urine Collection A plastic urine collection bag with hypoallergenic skin adhesive is used to collect a urine specimen from an infant or small child who is not yet potty trained. The patient’s genital area is cleaned and dried before the bag is taped to the skin. The bag is placed around the vagina of a female and over the penis of a male. A diaper is placed over the collection bag. The patient is checked every 15 minutes until an adequate specimen is obtained. The bag is then removed, sealed, labeled, and sent to the lab as soon as possible. A 24-hour specimen can be obtained by using a special collection bag with a tube attached that allows the bag to be emptied periodically. 444 UNIT IV: SPECIAL PROCEDURES AMNIOTIC FLUID Amniotic ﬂuid is the clear, almost colorless to pale-yellow ﬂuid that ﬁlls the membrane (amnion or amniotic sac) that surrounds and cushions a fetus in the uterus. It is preferably collected after 15 weeks of gestation (pregnancy) and is obtained by a physician using a procedure called transabdominal amniocentesis. The procedure, which is typically performed with ultrasound guidance, involves inserting a needle through the mother’s abdominal wall into the uterus and aspirating approximately 10 mL of ﬂuid from the amniotic sac. Amniotic ﬂuid can be analyzed to detect genetic disorders such as Down’s syndrome, identify hemolytic disease resulting from blood incompatibility between the mother and fetus, and determine gestational age. However, the most common reasons for testing amniotic ﬂuid are to detect problems in fetal development (particularly neural tube defects such as spina biﬁda) and assess fetal lung maturity. Genetic disorders can be detected by chromosome studies done on fetal cells removed from the ﬂuid, although the procedure has for the most part been replaced by studies on chorionic villi or placental tissue because it can be obtained earlier in the gestational period than amniotic ﬂuid. Hemolytic disease can be detected by measuring bilirubin levels. Although ultrasonography has become the accepted means of estimating gestational age, amniotic ﬂuid creatinine levels have also been used to estimate gestational age because these levels are related to fetal muscle mass. Problems in fetal development can be detected by measuring alpha-fetoprotein (AFP), an antigen normally present in the human fetus that is also found in amniotic ﬂuid and maternal serum. Abnormal AFP levels may indicate problems in fetal development such as neural tube defects or the potential for Down’s syndrome. AFP testing is initially performed on maternal serum, and abnormal results are conﬁrmed by amniotic ﬂuid AFP testing. Because normal AFP levels are different in each week of gestation, it is important that the gestational age of the fetus be included on the specimen label. AFP is present in the blood of males and nonpregnant females in certain pathological conditions. Fetal lung maturity can be assessed by measuring the amniotic ﬂuid levels of substances called phospholipids, which act as surfactants to keep the alveoli of the lungs inﬂated. Results are reported as a lecithin-to-sphingomyelin (L/S) ratio. Lungs are most likely to be immature if the L/S ratio is less than 2. Amniotic ﬂuid testing to assess fetal lung maturity may be ordered on or near the patient’s due date and is often ordered stat when the fetus is in distress. Amniotic ﬂuid is normally sterile and must be collected in a sterile container. The specimen should be protected from light to prevent breakdown of bilirubin and delivered to the laboratory ASAP. Specimens for chromosome analysis must be kept at room temperature. Specimens for some chemistry tests must be kept on ice. Follow laboratory protocol. Want to have some fun? See if you can unscramble a word from this section in Knowledge Drill 13-2 in the WORKBOOK. CEREBROSPINAL FLUID Cerebrospinal ﬂuid (CSF) is a clear, colorless liquid that surrounds the brain and spinal cord. CSF has many of the same constituents as blood plasma. Specimens are obtained by a physician; most often through lumbar puncture (spinal tap). The primary reason for collecting CSF is to diagnose meningitis. It is also used to diagnose other disorders such as brain abscess, CNS cancer, and multiple sclerosis. Routine tests performed on spinal ﬂuid include cell counts, chloride, glucose, and total protein. Other tests are performed if indicated. CSF is generally collected in three special sterile tubes numbered in order of collection. Laboratory protocol dictates which tests are to be performed on each particular tube unless the physician indicates otherwise. Normally, the ﬁrst tube is used for chemistry and immunology tests, the second for microbiology studies, and the third for cell counts. CSF should be kept at room temperature, delivered to the lab stat, and analyzed immediately. CHAPTER 13: NONBLOOD SPECIMENS AND TESTS 445 GASTRIC FLUID/GASTRIC ANALYSIS Gastric ﬂuid is stomach ﬂuid. A gastric analysis examines stomach contents for abnormal substances and measures gastric acid concentration to evaluate stomach acid production. A basal gastric analysis involves aspirating a sample of gastric ﬂuid by means of a tube passed through the mouth and throat (oropharynx) or nose and throat (nasopharynx) into the stomach after a period of fasting. This sample is tested to determine acidity prior to stimulation. After the basal sample has been collected, a gastric stimulant, most commonly histamine or pentagastrin, is administered intravenously and several more gastric samples are collected at timed intervals. All specimens are collected in sterile containers. The role of the phlebotomist in this procedure is to help label specimens and draw blood for serum gastrin (a hormone that stimulates gastric acid secretion) determinations. NASOPHARYNGEAL SECRETIONS The nasopharynx is comprised of the nasal cavity and pharynx. Nasopharyngeal (NP) secretions are cultured to detect the presence of microorganisms causing diphtheria, meningitis, pertussis (whooping cough), and pneumonia. NP specimens are collected using a sterile Dacron or cotton-tipped ﬂexible wire swab. The swab is inserted gently into the nose and passed into the nasopharynx. There it is gently rotated, then carefully removed, placed in a sterile tube containing transport medium, labeled, and delivered to the lab. SALIVA Saliva (ﬂuid secreted by glands in the mouth) is increasingly being used to monitor hormone levels and detect alcohol and drug abuse because it can be collected quickly and easily in a noninvasive manner. In addition, detection of drugs in saliva indicates recent drug use. Numerous kits are available for collecting and testing saliva specimens. Many are point-of-care tests. Saliva specimens for hormone tests, however, are typically frozen to ensure stability and sent to a laboratory for testing. SEMEN Semen (seminal ﬂuid) is the sperm-containing thick yellowish-white ﬂuid discharged during male ejaculation. It is analyzed to assess fertility or determine the effectiveness of sterilization following vasectomy. It is also sometimes examined for forensic (or legal) reasons (e.g., criminal sexual investigations). Semen specimens are collected in sterile or chemically clean containers and must be kept warm, protected from light, and delivered to the lab immediately. KEY POINT A semen specimen should not be collected in a condom unless it is one speciﬁcally designed for specimen collection. Regular condoms often contain spermicides (substances that kill sperm) that invalidate test results. SEROUS FLUID Serous ﬂuid is the pale-yellow, watery, serum-like ﬂuid found between the double-layered membranes enclosing the pleural, pericardial, and peritoneal cavities. It lubricates the membranes and allows them to slide past one another with minimal friction. The ﬂuid is normally present in small amounts, but volumes increase when inﬂammation or infection is present or when serum protein levels decrease. An increase in ﬂuid volume is called an effusion. Accumulation of excess serous ﬂuid in the peritoneal cavity is called ascites (a-si’ tez), and the ﬂuid is referred to as ascitic ﬂuid. 446 UNIT IV: SPECIAL PROCEDURES Do you know what the word elements in pericardial mean? Practice your wordbuilding skills with WORKBOOK Skills Drill 13-2. Serous ﬂuids can be aspirated for testing purposes or when increased amounts are interfering with the normal function of associated organs. A physician performs the procedure. Fluid withdrawn for testing is typically collected in EDTA tubes if cell counts or smears are ordered, in heparin or sodium ﬂuoride tubes for chemistry tests, in nonanticoagulant tubes for biochemical tests, and in sterile heparinized tubes for cultures. The type of ﬂuid should be indicated on the specimen label. Serous ﬂuids are identiﬁed according to the body cavity of origin as follows: Pleural ﬂuid: aspirated from the pleural space, or cavity, surrounding the lungs Peritoneal ﬂuid: aspirated from the abdominal cavity Pericardial ﬂuid: aspirated from the pericardial cavity surrounding the heart SPUTUM Sputum is mucus or phlegm that is ejected from the trachea, bronchi, and lungs through deep coughing. Sputum specimens are sometimes collected in the diagnosis or monitoring of lower respiratory tract infections such as tuberculosis (TB), caused by Mycobacterium tuberculosis. KEY POINT The microbe that causes TB is called an acid-fast bacillus (AFB), and the sputum test for TB is often called an AFB culture. First morning specimens are preferred, as secretions tend to collect in the lungs overnight and a larger volume of specimen can be produced. It is also best to collect the specimen at least 1 hour after a meal to minimize the risk that the patient will gag or vomit. The patient must ﬁrst remove dentures if applicable, then rinse his or her mouth and gargle with water to minimize contamination with mouth ﬂora and saliva. The patient is instructed to take three or four slow, deep breaths, inhaling to full capacity and exhaling fully, then to cough forcefully on the last breath and expectorate (cough up and expel sputum) into a special sterile container (Fig. 13-3). The process is repeated until a sufﬁcient amount of sputum is obtained. A minimum of 3 to 5 mL is typically required for most tests. KEY POINT The patient must cough up material from deep in the respiratory tract and not simply spit into the container. Specimens are transported at room temperature and require immediate processing upon arrival in the laboratory to maintain specimen quality. SWEAT Sweat is analyzed for chloride content in the diagnosis of cystic ﬁbrosis, predominantly in children and adolescents under the age of 20. Cystic ﬁbrosis is a disorder of the exocrine glands that affects many body systems but primarily the lungs, upper respiratory tract, liver, and pancreas. Patients with cystic ﬁbrosis have abnormally high levels (two to ﬁve times normal) of chloride in their sweat, which can be measured by the sweat chloride test. The test involves transporting pilocarpine (a sweat-stimulating drug) into the skin by means of electrical stimulation from electrodes placed on the skin, a process called iontophoresis. The forearm is the preferred site, but the leg or thigh may be used on infants or toddlers. Sweat is collected, weighed to determine its volume, and analyzed for chloride content. (The sweat chloride testing procedure is explained in Chapter 11 under “Point-of-Care Testing.”) Sweat specimens can also be used to detect illicit drug use. Sweat is collected on patches placed on the skin for extended periods of time and then tested for drugs. CHAPTER 13: NONBLOOD SPECIMENS AND TESTS 447 Figure 13-3 A sputum specimen container. SYNOVIAL FLUID Synovial ﬂuid is a clear, pale-yellow, viscous ﬂuid that lubricates and decreases friction in movable joints. It normally occurs in small amounts but increases when inﬂammation is present. It can be tested to identify or differentiate arthritis, gout, and other inﬂammatory conditions. It is typically collected in three tubes: an EDTA or heparin tube for cell counts, identiﬁcation of crystals, and smear preparation; a sterile tube for culture and sensitivity; and a nonadditive tube for macroscopic appearance, chemistry, and immunology tests and to observe clot formation. Other Nonblood Specimens BUCCAL SWABS Collection of a buccal (cheek) swab is a less invasive, painless alternative to blood collection for obtaining cells for DNA analysis. The phlebotomist collects the sample by gently massaging the mouth on the inside of the cheek with a special swab. DNA is later extracted from cells on the swab. BONE MARROW Because it is the site of blood cell production, bone marrow is sometimes aspirated and examined to detect and identify blood diseases. A bone marrow biopsy may be performed at the same time. To obtain bone marrow, a physician inserts a special large-gauge needle into the bone marrow in the iliac crest (hip bone) or sternum (breastbone). Once the bone marrow is penetrated, a 10-mL or larger syringe is attached to the needle to aspirate 1.0 to 1.5 mL of specimen. A laboratory hematology technologist is typically present and makes special slides 448 UNIT IV: SPECIAL PROCEDURES from part of the ﬁrst marrow aspirated. Additional syringes may be attached to collect marrow for other tests such as chromosome studies or bacterial cultures. Part of the ﬁrst sample may be placed in an EDTA tube for other laboratory studies. Remaining aspirate is sometimes allowed to clot and placed in formalin or another suitable preservative and sent to histology for processing and examination. In an alternate method, blood and particles from the EDTA tube are ﬁltered through a special paper. The ﬁltered particles are then folded in the paper and placed in formalin. If a bone marrow biopsy is collected at the same time, the cylindrical core of material obtained is touched lightly to the surface of several clean slides before being placed in a special preservative solution. The slides are air-dried and later ﬁxed with methanol and stained with Wright’s stain in the hematology department. The biopsy specimen and several slides are sent to the histology department for processing and evaluation. The remaining slides including biopsy touch slides are sent to the hematology department for staining and evaluation under the microscope. BREATH SAMPLES Breath samples are collected and analyzed for hydrogen content in one type of lactose tolerance test and to detect the presence of Helicobacter pylori (H. pylori), a type of bacteria that secretes substances that damage the lining of the stomach and causes chronic gastritis, which can lead to peptic ulcer disease. C-Urea Breath Test A common test used to detect H. pylori is the C-urea breath test (C-UBT). This test is based on the fact that H. pylori produces urease, an enzyme that breaks down urea but is not normally present in the stomach. To perform the test, a baseline breath sample is collected, after which the patient drinks a special substance that contains synthetic urea. The synthetic urea contains a form of carbon called carbon-13. If H. pylori organisms are present, the urease they produce will break down the synthetic urea and in the process release carbon dioxide (CO2) that contain carbon-13. The CO2 will be absorbed into the bloodstream and exhaled in the patient’s breath. The patient breathes into a special Mylar balloon or other collection device at speciﬁed intervals. The breath specimens are analyzed for carbon-13 content. If carbon-13 is found in amounts higher than those in the baseline sample, H. pylori is present in the stomach. Hydrogen Breath Test The hydrogen breath test helps identify problems with the digestion of carbohydrates such as lactose (milk sugar) and fructose (fruit sugar) and is thought to be the most accurate lactose tolerance test. It can also be used to detect bacterial overgrowth in the small intestine. The principle behind the test is that hydrogen gas is produced when intestinal bacteria ferment carbohydrates such as lactose, fructose, or lactulose (used to detect bacterial overgrowth). Some of the hydrogen is absorbed into the bloodstream and transported to the lungs, where it is exhaled during normal breathing. To prepare for the test, the patient must not have taken antibiotics for at least 2 weeks before the test and must avoid certain foods for 24 hours prior to the test. The patient must be fasting on the day of the test and is asked to refrain from vigorous exercise and smoking for 30 minutes prior to and during the test. On the day of the test, a baseline breath sample is taken by having the patient exhale into a special bag or device. Then the patient is given a drink that, depending on the type of test, contains a measured amount of lactose, fructose, or lactulose. Additional breath samples are collected at regular intervals, typically, every 30 minutes for up to 3 hours, depending on the amount of hydrogen detected in the samples. For those given lactose or fructose, increased hydrogen levels in the breath samples respectively indicate increased lactose or fructose in the intestinal tract, most likely as a result of metabolism. For those given lactulose, if bacterial overgrowth is present, increased hydrogen levels appear twice; the ﬁrst time when the lactulose reaches bacteria in the small intestine and the second time when it reaches bacteria in the colon. CHAPTER 13: NONBLOOD SPECIMENS AND TESTS 449 FECES (STOOL) Examination of fecal specimens (feces or stool) is helpful in the evaluation of gastrointestinal disorders. Stool specimens can be evaluated for the presence of intestinal parasites and their eggs (ova and parasites, or O&P), checked for fat and urobilinogen content, cultured to detect the presence of pathogenic bacteria (e.g., C. difﬁcile and Salmonella) and viruses, and tested for the presence of occult (hidden) blood using the guaiac test. Clostridium difﬁcile (C. difﬁcile) is a bacterium that can inhabit the intestinal tract and proliferate at the expense of normal bacteria in patients on antibiotic therapy. Although it is not commonly found in healthy adults, it is frequently found in hospitalized patients and is implicated as a causative agent of hospital-acquired diarrhea. Although cases are usually mild and subside when the antibiotic is discontinued, symptoms can persist and may become severe in some individuals. Stool specimens are normally collected in clean, dry, wide-mouthed containers that should be sealed and sent to the laboratory immediately after collection. Special containers with preservative are available for ova and parasite collection (Fig. 13-4). Preserved specimens can usually be kept at room temperature. Large gallon containers, similar to paint cans, are used for 24-, 48-, and 72-hour stool collections for fecal fat and urobilinogen; these specimens must normally be refrigerated throughout the collection period. Consult the facility procedure manual for test-speciﬁc collection and handling requirements. Special test cards, such as Hematest (Miles Inc., Elkhart, IN) and Hemoccult (Smith-Kline Diagnostics, San Jose, CA), are often given to outpatients to collect stool specimens for fecal occult blood testing (FOBT). The patient is usually instructed to follow a meat-free diet for 3 days prior to the test. Patients are then instructed to collect separate specimens for 3 successive days. Cards can be mailed in or brought to the lab after collection. HAIR Samples of hair are sometimes collected for trace and heavy metal analysis and the detection of drugs of abuse. Use of hair samples for drug testing is advantageous because hair is easy Figure 13-4 Ova and parasite specimen containers. 450 UNIT IV: SPECIAL PROCEDURES Figure 13-5 A throat swab and transport tube. to obtain and cannot easily be altered or tampered with. Hair shows evidence of chronic drug use rather than recent use. Although the use of hair for drug testing is on the rise, lack of standardization in this area has held up widespread acceptance. View the Throat Swab Collection and Rapid Detection of Strep procedure videos at http://thepoint.lww. com/McCall5e. THROAT SWABS Throat swab specimens are most often collected to aid in the diagnosis of streptococcal (strep) infections. Nursing staff usually collect throat culture specimens on inpatients. Phlebotomists commonly collect throat culture specimens on outpatients. A throat culture is typically collected using a special kit containing a sterile polyester-tipped swab in a covered transport tube containing transport medium (Fig. 13-5). The procedure for throat culture specimen collection is shown in Procedure 13-4. Throat swabs for rapid strep tests are collected in a similar manner. TISSUE SPECIMENS Tissue specimens from biopsies may also be sent to the laboratory for processing. (A biopsy is the removal of a tissue sample for examination.) Most tissue specimens arrive at the laboratory in formalin or another suitable solution and need only be accessioned and sent to the PROCEDURE 13-4 Throat Culture Specimen Collection PURPOSE: To provide instruction in how to properly collect a throat culture specimen EQUIPMENT: Requisition, specimen label, sterile container with swab and transport medium Step Rationale 1. Wash hands and put on gloves. The phlebotomist may wish to wear a mask and goggles. Follow facility protocol. Aids in infection control. Throat culture collection can cause the patient to have a gag reﬂex or cough. 2. Open container and remove swab in an aseptic manner. Swab sterility must be maintained for accurate interpretation of results. 3. Stand back or to the side of the patient. Helps avoid droplet contact if the patient coughs. 4. Instruct the patient to tilt back the head and open the mouth wide. Allows adequate evaluation of the collection site and ease in specimen collection. CHAPTER 13: NONBLOOD SPECIMENS AND TESTS 451 PROCEDURE 13-4 Throat Culture Specimen Collection (Continued) Step Rationale 5. Direct light onto the back of the throat using a small ﬂashlight or other light source. Illuminates areas of inﬂammation, ulceration, exudation, or capsule formation. 6. Depress the tongue with a tongue depressor and ask the patient to say “ah.” Depressing the tongue helps avoid touching other areas of the mouth and contaminating the sample during collection. Saying “ah” raises the uvula (soft tissue hanging from the back of the throat) out of the way. 7. Swab both tonsils, tonsilar crypts (crevasses), the back of the throat, and any areas of ulceration, exudation, or inﬂammation, being careful not to touch the swab to the lips, tongue, or uvula. Standard protocol that ensures sampling of the problem area. Touching other areas of the mouth can contaminate the swab with microbes from the oral cavity and not the throat. Touching the uvula can cause a gag reﬂex. 8. Maintain tongue depressor position while removing the swab and then discard it. Keeping the tongue depressor in place until the swab is removed prevents the tongue from contaminating the swab. 9. Place the swab back in the transport tube, embed in medium, and secure cover. (Follow instructions to crush ampule and release medium ﬁrst if applicable.) The transport medium keeps the microbes alive until they can be cultured in the laboratory. 10. Label specimen. Prompt labeling is essential to ensure correct specimen identiﬁcation. 11. Remove gloves and sanitize hands. Proper glove removal and hand decontamination prevents the spread of infection. 12. Arrange transport or deliver to the laboratory as soon as possible. Timely processing is necessary to prevent over growth of normal ﬂora. proper department. However, with more biopsies being performed in outpatient situations, a phlebotomist in specimen processing may encounter specimens that have not yet been put into the proper solution. It is important for the phlebotomist to check the procedure manual to determine the proper handling for any unfamiliar specimen. (For example, tissues for genetic analysis should not be put in formalin.) Improper handling can ruin a specimen from a procedure that is, in all probability, expensive, uncomfortable for the patient, and not easily repeated. STUDY AND REVIEW QUESTIONS See the EXAM REVIEW for more study questions. 1. Additional information typically required on a nonblood specimen label includes the: a. billing code. c. physician. b. party to be charged. d. specimen type. 2. Which type of urine specimen is used to detect UTI? a. 2-hour c. Clean catch b. 24-hour d. Midstream

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