Urine & Body Fluid Analysis Exam 1 Questions and Answers

Components of the urinary system - ANS Kidneys, ureters, bladder, urethra Major functions of the kidneys - ANS -Regulation of body fluids, acid-base balance, electrolyte balance -Excretion of waste products and foreign chemicals -Secretion of hormones (EPO) -Maintaining blood pressure Renal function is influenced heavily by - ANS blood volume, pressure, composition and hormones from the adrenal and pituitary glands; *circulatory system is crucial* What are the three major processes that lead to the formation of urine - ANS 1) Filtration 2) Reabsorption 3) Secretion Filtration - ANS Occurs in the glomerulus; renin-angiotensin-aldosterone feedback system Reabsorption - ANS Movement from filtrate to blood; filtered renal plasma is called "ultrafiltrate" Secretion - ANS Movement from blood to filtrate; removes unneeded foreign waste substances not filtered by the glomerulus; mostly occurs in distal convoluted tubule What is the functional unit of the kidney? - ANS nephron; about 1-1.5 million present in each kidney Function of the glomerulus - ANS Filtration of the blood/ filtration of water and dissolved substances from the plasma Function of the tubules - ANS Reabsorption of substances: glucose, NaCl, amino acids, potassium, water, calcium, urea Function of the Loop of Henle - ANS Recovery of water and sodium chloride from the urine Role of Antidiuretic hormone (ADH) - ANS -secreted by pituitary gland -regulates the reabsorption of water in the distal convoluted tubule & collected tubule What is tubular secretion? - ANS Movement from blood to filtrate Filtration: Renin-angiotensin-aldosterone feedback system - ANS -Maintains blood pressure of the arterioles at a relatively constant rate by regulation of the *dilation of the afferent arteriole* and *constriction of the efferent arteriole* -Enzyme *renin* is produced by the juxtaglomerular apparatus -Renin is released in response to decreased blood volume or decreased blood pressure (decreased sodium) What is the area of the nephron responsible for the secretion of renin? - ANS Juxtaglomerular apparatus Composition of glomerular ultrafiltrate - ANS Ultrafiltrate has no cells (RBCs/WBCs) and no proteins. In comparison, plasma also does not have cells but DOES have proteins. Renal threshold - ANS Maximum capacity of tubules to reabsorb Glucose has a renal threshold of: - ANS 160-180 mg/dL Active vs. passive reabsorption - ANS Active requires energy and passive does not require energy Reabsorption process - ANS Movement from filtrate to blood; epithelial cells lining the proximal tubule provide a large surface area to help reabsorb 80% of the ultrafiltrate Which substances are reabsorbed during the reabsorption process - ANS Glucose, NaCl, amino acids, potassium, water, calcium, urea Role of the kidney in ion secretion and acid-base balance - ANS H+ ions secreted, ammonium ions secreted, sodium ions reabsorbed, bicarbonate reabsorbed/secreted What is the countercurrent multiplier mechanism - ANS Mechanism that expends energy to create a concentration gradient which enables water reabsorption to produce concentrated urine Explain ADH hormone - ANS -antidiuretic hormone -secreted by pituitary gland -regulates the reabsorption of water in the distal convoluted tubule & collecting tubule Summarize the process of urine formation - ANS 1. Filtration from blood into nephron 2. Reabsorption from filtrate into blood 3. Tubular secretion from blood into filtrate 4. Reabsorption of water under effects of ADH Reference range for daily average volume of urine for adults: - ANS mL/day........ but can range from 600-2000 mL/day Polyuria - ANS Abnormal increase in urine volume (2500 mL/day) Oliguria - ANS Abnormal decrease in urine volume (500 mL/day) Anuria - ANS Complete suppression of urine formation (100 mL/day) during 2-3 days of high fluid intake Six major constituents that normally appear in urine: - ANS Urea, NaCl, Potassium, Sulfate, Phosphate, Creatine Two major components of urine? - ANS Urea & NaCl Urine must be examined within _______ hours of collection? (Unless preserved) - ANS 2 Purpose of random collection - ANS Routine screening Purpose of midstream (clean catch) collection - ANS Routine screening; bacterial culture Purpose of first morning collection - ANS Routine screening; pregnancy tests Purpose of fasting (second morning) collection - ANS Diabetic screening; pregnancy tests Purpose of glucose tolerance test collection - ANS Accompanies blood samples in glucose tolerance test Purpose of 2-hour post prandial collection - ANS Diabetic monitoring Purpose of 24-hour timed collection - ANS Quantitative chemical tests Purpose of catheterized collection - ANS Bacterial culture Purpose of suprapubic aspiration collection - ANS Bladder urine for bacterial culture; cytology Purpose of three-glass collection - ANS Differentiate UTI versus prostate infection Color change in unpreserved urine - ANS Oxidation of substances Clarity change in unpreserved urine - ANS Increased turbidity Odor change in unpreserved urine - ANS Increased strength (bacteria) pH change in unpreserved urine - ANS Increases as bacteria converts urea to ammonia Bilirubin change in unpreserved urine - ANS Decreases due to photooxidation Glucose change in unpreserved urine - ANS Decreases due to metabolism by microorganism Ketone change in unpreserved urine - ANS Volatilization Nitrite change in unpreserved urine - ANS Increases when bacteria present Urobilinogen change in unpreserved urine - ANS Decreases due to oxidation Crystals in unpreserved urine - ANS Appear due to cooling Cells and casts in unpreserved urine - ANS Decrease due to cellular degeneration Microorganisms in unpreserved urine - ANS Increase due to proliferation Most common method to preserve urine - ANS Refrigeration Pigments responsible for normal urine color - ANS Urochrome: light to dark yellow Uroerythrin: pink Urobilin: orange-brown White urine color - ANS Pathologic causes: chyle, lipids, pyuria Non-pathologic causes: vaginal creams Dark Yellow urine color - ANS Pathologic causes: dehydration Non-pathologic causes: strenuous exercise Amber urine color - ANS Pathologic causes: large amount of urobilin Non-pathologic causes: food color, medications Orange urine color - ANS Pathologic causes: bilirubin Non-pathologic causes: foods, vitamin B complex Red/pink urine color - ANS Pathologic causes: RBCs, hemoglobin, myoglobin Non-pathologic causes: beets, medications Brown/black urine color - ANS Pathologic causes: bilirubin, melanin Non-pathologic causes: iron compounds, medications Yellow/Green/Brown urine color - ANS Pathologic causes: bilirubin oxidized Non-pathologic causes: vitamins Green/Blue-green urine color - ANS Pathologic causes: Pseudamonas infection Non-pathologic causes: medications Clear red urine indicates: - ANS Hemoglobinuria (red plasma) OR myoglobinuria (clear plasma) Cloudy red urine indicates: - ANS RBCs present (hematuria) Yellow foam in urine indicates: - ANS Bilirubin White foam in urine indicates: - ANS Protein Non-pathologic causes of urine turbidity - ANS Mucus, crystals, semen Pathologic causes of urine turbidity - ANS RBCs, WBCs, bacteria/yeast Specific gravity - ANS Measures ability of kidney to concentrate urine; density of solution compared to density of pure water; measured by refractometer or reagent strip Normal Specific Gravity - ANS 1.003 (hydrated) - 1.035 (dehydrated) Osmolality - ANS Concentration per mass of solvent; depends on number of particles only; measured by freezing point (FP) depression Osmolality normal reference range - ANS 500-850 mOsm/kg water How to calibrate a refractometer - ANS Used distilled water, adjust screw to 1.000 if necessary; assay urine controls with low, medium, and high values at the beginning of each day Specimens with specific gravity readings exceeding scale (1.035) - ANS Dilute with distilled water and re-assay; multiply decimal portion of reading by dilution factor; can be caused by radiographic dye Isosthenuric - ANS 1.010 SG Hyposthenuric - ANS 1.010 SG Hypersthenuric - ANS 1.010 SG What are the different classifications of urine clarity? - ANS Clear, hazy, cloudy, milky, turbid What instrument is used to measure specific gravity? What is the principle of this measure? - ANS Refractometer - bending of light through the sample Normal value of pH on reagent strip - ANS Normal value: 4.6-8.0 Reagents used to test pH - ANS Methyl red and bromothymol blue Clinical significance of testing pH - ANS Identifying defects in kidney's ability to maintain acid-base balance; aids in management of conditions requiring maintenance of specific pH; identifying contaminated specimen Interpretation of pH on reagent strip - ANS Red = lower pH (~5.0) Yellow/green = average pH (~7.0) Dark blue = higher pH (~8.5) Normal value of protein on reagent strip - ANS 150 mg/24 hours Reagents used for protein on reagent strip - ANS H+ ions Clinical significance of testing protein - ANS Early indicator of renal disease, grouped as: pre-renal, renal, or post-renal Pre-renal proteinuria - ANS Overflow proteinuria; seen in severe infection/inflammation Renal proteinuria - ANS Defective filtration barrier; defective tubular reabsorption Post-renal proteinuria - ANS Proteins enter the ureters, bladder, or urethra due to infection/inflammation or injury; UTI, injury, menstrual contamination Interpretation of protein on reagent strip - ANS Negative/trace = yellow High protein = green to dark green Confirmatory test for protein reaction - ANS Sulfosalicyclic acid (SSA) - performed on urine with high pH ( 8.5) AND positive protein Glucose normal value on reagent strip - ANS Negative Reagents used for glucose reagent strip - ANS Glucose oxidase, peroxidase Clinical significance of testing glucose - ANS Monitoring glycosuria Interpretation of glucose reagent strip - ANS Negative result = light green Presence of glucose = Darker green/brown High levels of glucose = Deep red Confirmatory test for glucose & other reducing substances - ANS Clinitest - copper reduction test Normal result of ketones on reagent strip - ANS Negative Reagents used for ketones on reagent strip - ANS Sodium nitroprusside Clinical significance of testing ketones - ANS Starvation, malabsorption, strenuous exercise, vomiting, diabetes mellitus Critical value of ketones - ANS 80 mg/dL Interpretation of ketones on reagent strip - ANS Nude color = negative/normal Presence of ketones = pink High levels of ketones = dark pink & red Hematuria causes - ANS Kidney stones, trauma, infection, strenuous exercise Hemoglobinuria causes - ANS Blood transfusion reactions, severe burns, lysis of RBCs within urinary tract Myoglobinuria causes - ANS Muscular trauma, alcoholism, drug abuse, muscle wasting disease Normal result of blood on reagent strip - ANS Negative Reagents used for blood on reagent strip - ANS Hemoglobin peroxidase Clinical significance of testing for blood - ANS Monitoring hematuria, hemoglobinuria, and myoglobinuria Interpretation of blood on reagent strip - ANS Yellow: Negative/normal Yellow with blue specks: Non-hemolyzed result Green: small amount of blood present DARK green/black: large amount of blood present Hemolytic diseases (pre-hepatic problem) - ANS - bilirubin, +++ urobilinogen Hepatobiliary obstruction (post-hepatic problem) - ANS +++ bilirubin, normal urobilinogen Hepatitis (hepatic problem) - ANS + or - bilirubin, +++ urobilinogen Normal result of bilirubin on reagent strip - ANS Negative Reagents used for bilirubin on reagent strip - ANS Diazonium salt Clinical significance of testing for bilirubin - ANS Monitoring hemolytic diseases, hepatobilary obstruction, and hepatitis Interpretation of bilirubin on reagent strip - ANS Nude/yellow: Negative/normal Peach - brown: Moderate to high levels Bilirubin confirmatory test - ANS Ictotest - performed on ALL positive bilirubin specimens - purple stain indicates presence of bilirubin Normal result of urobilinogen on reagent strip - ANS ~0.2 - 1 mg/dL Reagent used for urobilinogen on reagent strip - ANS Ehrlich's reagent Clinical significance of testing for urobilinogen - ANS Monitoring hemolytic diseases, hepatobiliary obstruction and hepatitis Interpretation of urobilinogen on reagent strip - ANS Normal result: Nude/peach color High levels: Pink to dark pink Watson-Schwartz Test - ANS Urobilinogen vs. Porphobilinogen; uses chloroform and butanol Normal result of nitrite on reagent strip? - ANS Negative Reagents used for nitrite on reagent strip - ANS p-arsanilic acid, diazonium salt, tetrahydrobenoquinolin Clinical significance of testing for nitrite - ANS UTI presence Interpretation of nitrite on reagent strip - ANS Clear: Negative/normal Pink: Positive Normal value of leukocyte esterase (LE) on reagent strip - ANS Negative Reagents used for leukocyte esterase on reagent strip - ANS indoxylcarbonic acid ester, diazonium salt Clinical significance of testing leukocyte esterase - ANS Detects presence of WBCs, indicative of UTI, indicative of inflammation Interpretation of leukocyte esterase on reagent strip - ANS Colorless/clear: negative/normal Brown: small amount Purple: moderate-large amount Normal value of specific gravity on reagent strip - ANS 1.000-1.030 Clinical significance of testing specific gravity - ANS Monitors patient's level of hydration, detects loss of renal tubular concentrating ability, determines function of ADH Interpretation of specific gravity on reagent strip - ANS 1.000 dark blue ---- 1.030 orange A false negative for the glucose reagent test can be due to: - ANS Excessive amounts of absorbic acid Which of the ketones is/are detected by reagent strips: - ANS Acetoacetic acid Which of the following aids in the differentiation of hemoglobinuria and hematuria? - ANS Microscopic examination Which of the following can cause false-positive ketone results? - ANS Drugs containing free sulfhydryl groups What is the indication of a high leukocyte esterase content in the urine? - ANS Urinary tract infection A Watson-Schwartz test is performed on a urine specimen. The following results are seen: Chloroform tube: red in the bottom layer; Butanol tube: red color in the top layer. These results indicate the presence of: - ANS Urobilinogen The confirmatory test for a positive protein result by the reagent strip method uses: - ANS Sulfosalicyclic acid (SSA) The "double-indicator system" employed by commercial reagent strips to determine urine pH uses which two indicator dyes? - ANS Methyl red and bromothymol blue A patient's urinalysis revealed a positive bilirubin and a normal urobilinogen level. These results are associated with: - ANS Biliary obstruction (post-hepatic problem) Which of the following proteins originates from renal tubular epithelial cells within the urinary tract? - ANS Uromodulin The reagent strip reaction that requires the longest reaction time is the: - ANS Leukocyte esterase (LE) The CLS accidentally performs an SSA test on a specimen with a negative protein reagent strip test. However, she becomes concerned, because the SSA was positive with a 2+ result. What could be a cause of this discrepancy? - ANS A protein other than albumin is present in the urine. Which of the following substances or actions can result in a false-positive nitrite result? - ANS Improper specimen storage The ketone reagent strip is based on the reactivity of ketones with: - ANS Nitroprusside Which of the following best describes the chemical principle of the protein reagent strip test? - ANS The protein accepts hydrogen ions (H+) from the indicator dye, which results in a color change Which of the following urine results is most apt to be changed by inadequate storage conditions and prolonged exposure to light? - ANS Urobilinogen True or false: Bilirubin is a breakdown product of heme - ANS True Normally, daily urine protein excretion does not exceed: - ANS 150 mg/day The bilirubin reagent strip and tablet test (Ictotest) are based on: - ANS The combining of bilirubin with a diazonium salt Quality control of reagent strips is performed: - ANS Using positive and negative controls, when opening a new bottle of reagent strips, and at least once every 24 hours. Define uromodulin - ANS Tamm-Horsfall protein; one of the most abundant proteins found in urine; forms casts; originates from renal tubular epithelial cells within the urinary tract What are two tests that one should consider correlating with a positive leukocyte esterase reagent strip test? - ANS Nitrite and microscopic Which type of protein is typically detected by the reagent strip? - ANS Uromodulin/Tamm-Horsfall proteins, albumin, microglobulins What is the clinical correlation when a large amount of urobilinogen is detected in urine? - ANS More RBCs dying faster (sickle cell anemia) Which 3 molecules are classified as ketones? - ANS acetoacetate, acetone, b-hydroxybutyrate Steps in preparing urinary sediment for microscopic examination: - ANS 1. examine urine within 2 hours (or preserve) 2. mix and aliquot into centrifuge tube 3. volume of urine to be examined: 10-15 mL 4. time of centrifugation: 5 minutes 5. speed of centrifugation: ~2000 rpm 6. volume of sediment is examined and standardized Microscopic examination of urine techniques - ANS 1. keep light source low 2. fine adjustment should be continuously adjusted up and down 3. count ~10-15 different fields Sternheimer-Malbin stain (sedi-stain) - ANS Identifies WBCs, epithelial cells, and casts 2% acetic acid stain - ANS Distinguishes RBCs from WBCs, yeast, oil droplets, and crystals Lipid stains: Oil Red O and Sudan III - ANS Identifies free fat droplets and lipid-containing cells and casts Gram stain - ANS Identifies bacteria casts Hansel stain - ANS Identifies urinary eosinophils Prussian blue stain - ANS Identifies yellow-brown granules of hemosiderin in cells and casts RBC reference value in urinary sediment - ANS 0-3/HPF WBC reference value in urinary sediment - ANS 0-5/HPF Hyaline casts reference value in urinary sediment - ANS 0-1/LPF RTE reference value in urinary sediment - ANS Occ/HPF Transitional epithelial cell reference value in urinary sediment - ANS Occ/HPF Squamous epithelial cell reference value in urinary sediment - ANS Occ/LPF Bacteria and yeast reference value in urinary sediment - ANS Negative/HPF Abnormal crystal reference value in urinary sediment - ANS None/HPF Clinical significance of RBCs in urine - ANS Renal bleeding; glomerular damage ("dysmorphic") Positive reagent strip blood, but no RBCs in microscopic examination indicates: - ANS presence of hemoglobin or myoglobin Clinical significance of WBCs in urine - ANS Increased WBCs (pyuria) seen in renal disease, infections, inflammatory conditions; present in drug-induced nephritis, chronic UTI, renal transplant rejection Squamous epithelial cells - ANS From the male urethra and the female urethra lining; little diagnostic significance Transitional epithelial cells - ANS From the renal pelvis, ureters, bladder, and upper portion of the urethra; inflammation - increased numbers with abnormal morphology associated with acute inflammatory process, viral infection, or tumor; seen after invasive procedure (catheterization) Renal tubular epithelial cells - ANS From the proximal and distal convoluted tubules as well as the collecting duct; renal tubular damage Presence of bacteria in urine - ANS UTI Presence of yeast in urine - ANS Small, oval, retractile structure with buds and/or hyphae, very commonly confused with RBCs Presence of spermatozoa in urine - ANS Epileptic convulsions, nocturnal emissions, spermatorrhea, post-coitus Presence of mucus in urine - ANS Inflammation or irritation of the urinary tract Presence of oval fat bodies in urine - ANS Lipiduria, diabetes, nephrotic syndrome, extensive crush injuries Trichomonas vaginalis - ANS Most common sexually transmitted disease Presence of starch granules in urine - ANS Artifact from powder made from cornstarch Presence of fibers in urine - ANS Artifact What cell is MOST commonly associated with vaginal contamination? - ANS Squamous epithelial cells What are distinguishing characteristics of yeast in the urine sediment? - ANS Hyphae formation, budding forms True or false: If large numbers of yeast cells are present microscopically, then epithelial cells are present - ANS False True or false: If large numbers of casts are present microscopically, then the chemical test for protein should be positive - ANS True True or false: if white blood cells are present microscopically, then the chemical test for leukocyte esterase should be positive - ANS True True or false: if large numbers of red blood cells are present microscopically, then the chemical test for blood should be positive. - ANS True True or false: The number of eosinophils is increased in patients experiencing kidney transplant rejection. - ANS True Glitter cells are a microscopic finding of: - ANS White blood cells in hypotonic urine White blood cells can be difficult to distinguish from: - ANS RTE cells A technologist is having trouble differentiating between red blood cells, oil droplets, and yeast cells on a urine microscopy. Acetic acid should be added to the sediment to: - ANS Lyse the red blood cells True or false: neutrophils are enumerated on low power and reported as the average number per LPF. - ANS False True or false: neutrophils can be present in patients with renal infection - ANS True True or false: in hypotonic urine, neutrophils can be referred to as "glitter cells" due to swelling and movement - ANS True True or false: neutrophils are the most predominant WBC found in the urine - ANS True Which cell is the largest found in the urine? - ANS Squamous epithelial cell True or false: Red blood cells swell and can burst forming "ghost cells" in hypotonic urine - ANS True True or false: Dysmorphic red blood cells are often associated with renal tubular disease - ANS False True or false: Red blood cells are the "glitter cells" in hypotonic urine - ANS False True or false: red blood cells crenate in hypotonic urine - ANS False Which cells do we look at under LPF (10x)? - ANS casts, squamous epithelial cells Which cells do we look at under HPF (40x)? - ANS RBCs, WBCs, RTEs, transitional epithelial cells, bacteria, yeast, abnormal crystals Watson-Schwartz Test - ANS Used to differentiate urobilinogen from porphobilinogen - porphobilinogen is not normally found in urine; when present, it causes the urine to have red wine color. Porphobilinogen reacts with Ehrlich reagents & urobilinogen is extractable into chloroform and butanol