Introduction to Urinalysis Supplementary Notes PDF

AUBF Supplementary Notes Frederik Dekkers I. Introduction to Urinalysis - Discovery in 1694 of albuminuria ✓ History and Importance of Urinalysis - Albuminuria was detected by boiling urine ✓ Urine Composition ✓ Urin...

AUBF Supplementary Notes Frederik Dekkers I. Introduction to Urinalysis - Discovery in 1694 of albuminuria ✓ History and Importance of Urinalysis - Albuminuria was detected by boiling urine ✓ Urine Composition ✓ Urine Volume Thomas Bryant ✓ Specimen Collection - Published a book about “charlatans (pisse ✓ Specimen Rejection prophets)” or quack doctors ✓ Specimen Handling o Charlatans are self-proclaimed ✓ Type of Specimen physicians that are without medical credentials who are offering their URINE ANALYSIS (URINALYSIS) “service” to the public for a healthy Clinical and Laboratory Standards Institute (CLSI) fee defines urinalysis as: - His book inspired the passing of the first - “the testing of urine with procedures medical licensure laws in England commonly performed in an expeditious, reliable, accurate, safe, and cost-effective Invention of Microscope manner.” - 17th Century Reasons for performing urinalysis identified by CLSI - Dutch spectacle maker Zacharias Janssen is include: credited with making one of the earliest - aiding in the diagnosis of disease, compound microscope - screening asymptomatic populations for - Examination of urinary sediment began undetected disorders, - Thomas Addis began quantitating - and monitoring the progress of disease and microscopic sediment the effectiveness of therapy - Richard Bright introduced the concept of urinalysis as part of a doctor’s routine patient HISTORY AND IMPORTANCE examination in 1827 “Analyzing urine was actually the beginning of laboratory medicine.” 1930s - Number and complexity of urinalysis tests References to the study of urine: reached a point of impracticality - Ancient drawings of cavemen and - Urinalysis began to disappear from routine hieroglyphics examinations o Pictures of early physicians examining - But later on, it was rescued by modern testing a bladder-shaped flask of urine techniques o E.g. Edwin Smith Surgical Papyrus Why is urine specimen continually popular? “Although these physicians lacked the sophisticated 1. Urine is readily available and easily collected testing mechanisms now available, they were able to 2. Urine contains information, which can be obtain diagnostic information from such basic obtained by inexpensive laboratory tests, observations as color, turbidity, odor, volume, about many of the body’s major metabolic viscosity, and even sweetness (by noting that certain functions specimens attracted ants or tasted sweet).” URINE FORMATION First Methods used in ancient Urine Analysis - The kidneys are the main organ for urine - Ant Testing production - Taste Testing - It forms urine as an ultrafiltrate of plasma - Reabsorption of water and filtered substances Well-known names and Notable Ages in Urine essential to body function converts Analysis: approximately 170,000 mL of filtered plasma to the average daily urine output of 1200 mL Hippocrates - Wrote a book on “uroscopy” URINE COMPOSITION - 5th century BCE - Consists mainly of urea and other organic and inorganic chemicals dissolved in water Middle Ages - Normally 95% water and 5% solutes - Physicians studied the art of uroscopy - Urine examination became part of training as ORGANIC SUBSTANCES: a physician 1. UREA - Primary organic component. Product 1140 CE of protein and amino acid metabolism - Color charts had been developed; described 2. CREATININE the significance of 20 different colors - Product of creatine metabolism by muscles 3. URIC ACID - Product of nucleic acid breakdown in food and cells INORGANIC SUBSTANCES: Nocturia 1. CHLORIDE - An increase excretion of urine during the - Primary inorganic component. Found night in combination with sodium (table salt) and many other inorganic Polyuria substances - Increase in daily urine volume (greater than 2. SODIUM 2.5 L/day in adults and 2.5 to 3 mL/kg/day in - Sodium primarily from salt, varies by children intake - Often associated with diabetes mellitus and 3. POTASSIUM diabetes insipidus - Combined with chloride and other - Can be artificially induced by diuretics, salts caffeine, or alcohol which suppresses 4. PHOSPHATE secretion of antidiuretic hormone - Combines with sodium to buffer the blood 5. AMMONIUM - Regulates blood and tissue fluid acidity 6. CALCIUM - Combines with chloride, sulfate, and phosphate OTHER SUBSTANCES: - Hormones, vitamins, and medications - Cells, casts, crystals, mucus, and bacteria o Although not a part of the SPECIMEN COLLECTION original plasma filtrate, the Possible reasons for rejection: urine also may contain these - Specimens in unlabeled containers formed elements - Non-matching labels and requisition forms o Increased amounts of these - Specimens contaminated with feces or toilet formed elements are often paper indicative of disease. - Containers with contaminated exteriors - Specimens of insufficient quantity - Specimens that have been improperly transported SPECIMEN HANDLING Containers - Must be clean, dry, and leak-proof Factors that influence urine volume: - Disposable containers are advisable - Fluid intake - Applied screw top lids are less likely to leak - Fluid loss from nonrenal sources compared to snap-on lids - Variations in the secretion of antidiuretic - Should have a wide mouth hormone - Should be made of clear material to allow for - Need to excrete increased amounts of determination of color and clarity dissolved solids, such as glucose or salts - Recommended capacity is 50 mL o Allows 12mL specimen needed for Normal daily urine output: microscopic analysis - 1200 to 1500 mL o Additional specimen for repeat - 600 to 2000 mL is considered normal analysis o Enough room for the specimen to be Conditions that may affect urine volume: mixed by swirling the container Oliguria - Decrease in urine output Individually packaged sterile containers - Less than 1mL/kg/hr in infants o Used for microbiologic urine studies - Less than 0.5mL/kg/hr in children - Less than 400mL/day in adults Specially designed sterile containers - Commonly happens when the body is in the o Usually comes with a transfer straw state of dehydration o Transfer straw has a needle and an evacuated tube holder Anuria o Urine can be sterilely transferred to tubes - Cessation of urine flow containing preservatives for microbiology - May result from any serious damage to the testing and tubes with conical bottoms for kidneys or from a decrease in the flow of sediment analysis or round bottoms for blood to the kidneys automated reagent strip testing.  Labels URINE PRESERVATIVES - Urine specimen must be labeled properly with: o Patient's name o Identification number o Date and time of collection o Patient’s age and location o Healthcare provider’s name - Must be attached to the body of the container NOT ON THE LID - The label should not become detached if the container is refrigerated or frozen Requisitions - Can either be manual or computerized - Must accompany specimens delivered to the laboratory - Information on the form must match the information on the specimen label - The time the specimen is received by the laboratory must be recorded on the form SPECIMEN INTEGRITY TYPES OF URINE SPECIMEN - Should be delivered to the laboratory Special conditions that determine specimen type: promptly and tested within 2 hours - Time of collection - Specimens not delivered and tested within 2 - Length of collection hours must be refrigerated or have a chemical - Method of collection preservative - Patient’s dietary and medicinal intake Specimen Preservation 1. Random Specimen - Refrigeration at 2C to 8C - Most commonly received specimen - These temperature decreases bacterial - Collected at any time growth and metabolism - Useful for routine screening tests to detect - If the urine is to be cultured, it should be obvious abnormalities refrigerated during transit and kept - But may show erroneous results resulting refrigerated until cultured from dietary intake or physical activity just o Viability: up to 24 hours before collection - Use of chemical preservatives are alternatives if refrigeration is not possible 2. First Morning Specimen - Ideal screening specimen CHANGES IN UNPRESERVED URINE - It is a concentrated specimen, thereby assuring detection of chemicals and formed elements that may not be present in dilute random specimen - The specimen should be collected and delivered to the laboratory within 2 hours - Essential for preventing false-negative pregnancy tests and for evaluating orthostatic proteinuria 3. 24-Hour (or Timed) Specimen - A carefully timed specimen must be used to produce accurate quantitative results. Many solutes exhibit diurnal variations such as catecholamines, 17- hydroxysteroids, and electrolytes in which the lowest concentration is in the early morning and the highest concentration occurs in the afternoon - Patient must begin and end the collection period with an empty bladder 4. Catheterized Specimen - Collected under sterile conditions by passing a catheter through the urethra into the bladder - Usually used for bacterial culture 5. Midstream Clean-Catch Specimen 9. Drug Specimen Collection - Alternative to catheterized specimen - Correct collection procedures and - Safer, less traumatic method for obtaining documentation are necessary to ensure that urine for bacterial culture and routine the results are those of the specific individual urinalysis submitting the specimen. - Less contaminated by epithelial cells and - The chain of custody (COC) is the process that bacteria provides this documentation of proper - USE mild antiseptic towelettes sample identification from the time of DO NOT USE hexachlorophene or povidone- collection to the receipt of laboratory results. iodine (Strong bacterial agents) Requires: 6. Suprapubic Aspiration ✓ Photoidentification - Collected by external introduction of a needle ✓ Witness: same-gender collector through the abdomen into the bladder observe the collection of 30 to 45 mL - Provides a sample for bacterial culture that is of urine (60 mL) completely free of extraneous contamination ✓ Proper labeling should be followed to - Also used for cytologic examination establish a chain of custody Urine temperature must be taken within 4 7. Prostatitis Specimen minutes from time of collection (32.5 °C – 37.7 °C) to confirm the specimen has not been adulterated ✓ outside the range can indicated specimen contamination ✓ recollection of 2nd specimen ASAP may be necessary Urine color: inspect and identify signs of contaminants (ex. Add bluing dye to toilet water reservoir to prevent adultered specimen) Other indicators: Urine pH not >9.0; SG not