Urine and Other Nonblood Specimens and Tests PDF

Urine and Other Nonblood Specimens and Tests Prof. Maria Josephine G. Liao, RMT, MSPH Notes by me, Sen >:3 Nonblood Body Fluid Specimens These are liquid or semiliquid substances produced by the body. They are found in the intracellular and interstitial spaces and within various organs (e.g., the bl...

Urine and Other Nonblood Specimens and Tests Prof. Maria Josephine G. Liao, RMT, MSPH Notes by me, Sen >:3 Nonblood Body Fluid Specimens These are liquid or semiliquid substances produced by the body. They are found in the intracellular and interstitial spaces and within various organs (e.g., the bladder) and body spaces (e.g., joints). Urine Urine is the most frequently analyzed nonblood body fluid since it is readily available, easy to collect, and generally inexpensive to test. It can provide information on many of the body’s major metabolic functions. It also aids in: monitoring wellness, diagnosis and treatment of urinary tract infections, detection and monitoring of metabolic disease, and determining the effectiveness or complications of therapy. Types of Urine Specimen Random First Morning/8-Hour Specimen Fasting Timed o Tolerance Test Specimen o 2-Hour Post prandial specimen o 24-Hour Specimen o Double-Voided Specimen (Glucose, Ketone) Urine Collection Method Regular Voided Specimen Midstream Specimen Midstream Clean-Catch Specimen Catheterized Specimen Suprapubic Aspiration Pediatric Urine Collection Common Urine Tests Routine Urinalysis (UA) Collection: Midstream catch, preferably first-morning specimen Container: Clear, dry, chemically clean containers with tight-fitting lids. Transport to the laboratory immediately after collection. If urine specimens are not tested promptly, urine components can change. o cellular elements decompose o bilirubin breaks down to biliverdin o bacteria multiply Screens for urinary and systemic disorders Physical analysis o Color o Clarity o Odor o Volume o Specific gravity or Osmolality Chemical analysis o Bilirubin o Blood o Glucose o Ketones o pH o Leukocyte o Nitrite o Protein o Urobilinogen o SG Microscopic analysis o Cells o Crystals o Microorganisms Urine Culture and Sensitivity Requested on a patient with symptoms of urinary tract infection (UTI). Midstream clean-catch Inoculate in culture media (BAP, MAC) using 10 uL inoculating loop. Incubate for 18-24 hours. Perform ID and sensitivity testing. Urine Cytology Studies Performed to detect cancer, cytomegalovirus, and other viral and inflammatory diseases of the bladder and other structures of the urinary system. Examine cells from lining of urinary tract. Papanicolaou (PAP) stain. Examine as soon as possible. If delay is unavoidable, add 50% alcohol. Urine Drug Screening Performed to detect: o recreational drugs o anabolic steroids o prescription drugs Monitor therapeutic drug use. Confirm a diagnosis of drug overdose. Sample: Random (avoid bloody and highly alkaline/acidic). Urine Glucose and Ketone Testing Used to diagnose diabetic ketoacidosis and help differentiate between diabetic and nondiabetic coma. Reagent strip. Urine Pregnancy Testing Human chorionic gonadotropin (HCG) o hormone produced by cells within the developing placenta. o appears in serum and urine approximately 8 to 10 days after conception, or fertilization. First morning specimen is preferred. False Positive: o melanoma, tumors of the ovaries or testes, and certain types of cancer, including breast, lung, and kidney. Amniotic Fluid Amniotic fluid is a clear (colorless to pale-yellow) fluid that fills amniotic sac1. It is preferably collected after 15 weeks of gestation. The purpose of its collection is to: detect genetic disorders, identify hemolytic disease resulting from blood incompatibility between the mother and fetus, determine gestational age, detect problems in fetal development (particularly neural tube defects such as spina bifida) – measuring of AFP, and asses fetal lung maturity. Chromosome studies – detect genetic disorders. Bilirubin measurement – detect hemolytic disease. Creatinine measurement – estimate gestational age. Alpha-fetoprotein (AFP) – detect problems in fetal development. Neural tube defects Down’s syndrome Phospholipids measurement sphingomyelin L/S ratio) (lecithin-to- Assess fetal lung maturity. L/S ratio less than 2 = immature lungs Collection method and considerations: 1 Transabdominal amniocentesis. Sterile container, protected from light. Aspirate appx. 10 mL of fluid from amniotic sac. Transport ASAP. The fluid-filled sac that surrounds and cushions a fetus in the womb. Cerebrospinal Fluid (CSF) Cerebrospinal fluid is a clear, colorless liquid that surrounds the brain and spinal cord. It aids in the diagnoses of meningitis, brain abscess, CNS cancer, and multiple sclerosis. Method of collection: Lumbar Puncture (Spinal Tap) A spinal tap is performed in the lower, lumbar region of the spine. The spinal cord ends near the first or second lumbar vertebrae. To avoid injury to the spinal cord, the needle used to withdraw the CSF is inserted between the third and fourth or the fourth and fifth lumbar vertebrae, well below where the spinal cord ends. CSF Specimen Tubes: CSF is generally collected in three or four special sterile screw top tubes specifically numbered in order of collection. 1. 2. 3. 4. Chemistry & immunology Microbiology Cell count Cytology, other special tests, or an extra tube Most tests require a minimum of 1 mL of fresh fluid. CSF Specimen Handling: CSF should be kept at room temperature, delivered to the lab STAT, and analyzed immediately. Routine tests: Cell counts Chloride Glucose Total protein Gastric Fluid 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 gastrin2 determinations. Nasopharyngeal Secretions The nasopharynx is comprised of the nasal cavity and pharynx. Nasopharyngeal (NP) secretions can be cultured to detect the presence of microorganisms that cause diseases such as diphtheria, influenza, meningitis, pertussis (whooping cough), and pneumonia. Nasopharyngeal Specimen Collection NP specimens are collected using a sterile Dacron3, rayon4, 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. 2 A hormone that stimulates gastric acid secretion. A synthetic polyester (polyethylene terephthalate) with tough, elastic properties, used as a textile fabric. 4 A semi-synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products. 3 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 (i.e., within the previous few days). Numerous kits are available for collecting and testing saliva specimens. Many are POC tests. Saliva specimens for hormone tests, however, are typically refrigerated or 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 assault 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. 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 effusion. Serous fluids are identified according to the body cavity of origin as follows: Pleural fluid: This fluid is aspirated from the pleural space (cavity) surrounding the lungs by a procedure called pleurocentesis. Inflammation of the pleural membranes (pleura) is called pleuritis, and chest pain caused by the inflammation is called pleurisy. Peritoneal fluid: This fluid is aspirated from the abdominal cavity by a procedure called paracentesis. Inflammation of the peritoneum, the lining of the abdominal cavity, is called peritonitis. Pericardial fluid: This fluid is aspirated from the pericardial cavity surrounding the heart in a procedure called pericardiocentesis (or pericardial tap). Inflammation of the pericardium or pericardial space is called pericarditis. Ascites is the accumulation of excess serous fluid in the peritoneal cavity and the fluid is referred to as ascitic fluid. Serous Fluid Collection 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. 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 tuberculosis5. Microorganisms in sputum can be detected and identified by C&S testing and by microscopic identification on a specially stained slide made from the sputum. Sputum Collection First-morning specimens are preferred since 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 one hour after a meal to minimize the risk that the patient will gag or vomit. A minimum of 3 to 5 mL is typically required for most tests. Specimens are transported at room temperature and require immediate processing upon arrival in the laboratory to maintain specimen quality. 5 This microbe is often referred to as an acid-fast bacillus (AFB) because it resists decolorizing by acid after it has been stained. Likewise, the sputum test for TB is often called an AFB culture, and the slide made from sputum is often called an AFB smear Sweat Sweat is analyzed for chloride content in the diagnosis of cystic fibrosis (CF) predominantly in children and adolescents under the age of 20. CF is a disorder of the exocrine glands that affects many body systems but primarily the lungs, upper respiratory tract, liver, and pancreas. The sweat of patients with CF can be up to five times saltier than normal because their sweat contains two to five times the normal amount of chloride. The amount of chloride in sweat 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. Sweat specimens can also be used to detect long-term illicit drug use when urine testing is not practical. The sweat is collected on patches placed on the skin for extended periods of time (up to 14 days) and then tested for drugs. Synovial Fluid Synovial fluid is a clear, pale yellow, moderately viscous fluid that lubricates and decreases friction in movable joints. It normally occurs in small amounts but increases when inflammation is present. The procedure to collect synovial fluid is called joint aspiration or arthrocentesis. The fluid may be removed for both therapeutic (helps relieve pain and pressure) and diagnostic purposes. Synovial fluid analysis may be performed to help diagnose the cause of joint inflammation and swelling, identify or differentiate inflammatory and noninflammatory arthritis, and evaluate and manage joint diseases such as septic arthritis, gout, and other inflammatory conditions. Synovial Fluid Collection 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. Buccal Swabs Collection of a cheek, or buccal swab or oral specimen is a rapid, less invasive, and painless alternative to blood collection for obtaining cells for DNA analysis (plus, DNA is more easily extracted from buccal swabs than from blood samples). Cells from the swab can be used for paternity testing and to identify viruses such as herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2), oral human papillomavirus (HPV), and mumps virus. Because DNA analysis requires more DNA than is typically found in a buccal sample, a process called polymerase chain reaction (PCR) can be used to detect and amplify (i.e., make copies of) small segments of DNA. The process can target specific segments of DNA to aid in the type of analysis requested. Bown Marrow Bown marrow is the site of blood cell production and is sometimes aspirated and examined to detect and identify blood diseases. Bown Marrow Collection 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 to 1.5 mL of specimen. Tests done include: Hematologic studies (EDTA) Chromosome studies Bacterial Cultures Cell Cytology Breath Samples Breath samples are collected and analyzed in one type of lactose tolerance test, and to detect the presence of Helicobacter pylori (H. pylori). H. pylori is 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. 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 measures the amount of hydrogen exhaled to help identify problems with the digestion of carbohydrates such as lactose (milk sugar) and fructose (fruit sugar). It is thought to be the most accurate lactose tolerance test, and it can also be used to detect bacterial overgrowth in the small intestine (lactose, fructose, lactulose). Feces (Stool) Examination of fecal (stool) specimens can help identify disorders of the digestive tract, liver, and pancreas. Such disorders include gastrointestinal bleeding; parasite, bacteria, fungus or virus infection; malabsorption syndrome; and cancer. In addition to evaluation of physical characteristics, stool analysis may also include chemical, microscopic, and microbiological tests: Chemical tests include pH, qualitative and quantitative fecal fat, urobilinogen, detection of proteolytic enzymes such as trypsin and chymotrypsin, and identifying the presence of occult (hidden) blood using the guaiac test. Microscopic analysis can include looking for fecal fat (a qualitative fecal fat analysis) and muscle fibers, leukocyte detection, and ova and parasite (O&P) testing. O&P testing involves looking for parasites and their ova (eggs) or cysts. Examples of intestinal parasites include pinworms and Giardia lamblia. Microbiological analysis includes cultures to detect and identify infection with microorganisms such as Clostridium difficile (C. difficile or C. diff), Salmonella, Shigella, Campylobacter, enterohemorrhagic Escherichia coli (EHEC). Hair and Nail Clippings Hair is collected for trace and heavy metal analysis, detection of chronic drug use, and DNA analysis. Nail clippings can be used for heavy metal testing and must be taken from all 10 nails (either fingernails or toenails). Skin Tests Skin tests most often involve the intradermal (within the skin) injection of an allergenic substance (a substance that causes an immune response). Such tests are performed to determine whether an individual has encountered a specific allergen (antigen) and developed antibodies against it. Skin Prick Test The skin prick test is also called a puncture or scratch test and can check for allergic reactions to as many as 40 different substances at one time. This test is usually done to identify everyday allergens such as pollen, dust mites, mold, foods, and pet dander. The pricks can be done on the forearm or back, and the test is usually performed in a physician’s office. Tuberculin Test Mantoux tuberculin skin test or TST determines whether an individual has developed an immune response to Mycobacterium tuberculosis. Throat Swabs Throat swab specimens are most often collected to aid in the diagnosis of streptococcal (strep) throat infections. The swabs can be cultured in the microbiology department or used with a rapid strep screening test. A throat culture is typically collected using a special kit containing a sterile polyester-tipped swab in a covered transport tube containing transport medium. It is typically done on outpatients. 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 formalin6 or another suitable solution. 6 A dilution of formaldehyde that helps preserve the tissue and allows the use of other fixatives later if required