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| Which three processes compose the formation of urine? | Filtration, secretion, and reabsorption. |
| Which physiological system controls the regulation of blood flow to and within the kidneys? | The renin-angiotensin-aldosterone system. |
| What is the term for a substance that is not excreted in urine until its plasma concentration exceeds a specific limit? | Threshold substance. |
| When renal tubular function is lost, the specific gravity of urine typically fixes at what value? | 1.010 |
| Urine collected for routine bacteriologic culture should be plated within how many hours of collection if not refrigerated? | 2 hours. |
| At what temperature range should a urine sample be stored if plating for culture is delayed up to 24 hours? | $2^{\circ}C$ to $8^{\circ}C$. |
| Which urine color is correctly associated with the presence of bilirubin? | Dark yellow urine with yellow foam. |
| What color is urine containing homogentisic acid likely to turn upon standing? | Dark brown or black. |
| Which group of substances causes urine to produce red fluorescence under ultraviolet light ($360$ nm)? | Porphyrins (uroporphyrin and coproporphyrin). |
| Which clinical condition is associated with pale-yellow urine despite a high specific gravity? | Diabetes mellitus. |
| What does a cloudy pink urine appearance typically indicate? | The presence of intact red blood cells (hematuria). |
| Diabetes insipidus is characterized by a specific gravity consistently at or below what level? | 1.003 |
| Which test is used to detect porphobilinogen (PBG) in urine? | Ehrlich reaction (or Watson-Schwartz test). |
| The presence of melanin in urine causes the specimen to turn which color on standing? | Brown or black. |
| Which urine chemical test result is least likely to be affected by leaving the specimen at room temperature for several hours? | Protein. |
| In a 24-hour urine collection, what should be done with the very first void at the start time? | It should be voided and discarded. |
| Define 'oliguria' in terms of daily urine volume for an adult. | Urine production of less than $400$ mL/day. |
| Which urinary constituent contributes to specific gravity but not to osmolality? | Protein (colloids). |
| Specific gravity is a measure of _____. | Dissolved solute concentration. |
| Which method is the most accurate for measuring the concentration of dissolved solutes in urine? | Osmometry. |
| What is the chemical principle of the colorimetric reagent strip for specific gravity? | Ionic strength alters the $pK_{a}$ of a polyelectrolyte. |
| Urine pH tends to _____ as the specimen is stored at room temperature. | Increase (become more alkaline). |
| In renal tubular acidosis, what is the typical characteristic of urine pH? | Consistently alkaline. |
| What is the approximate reference range for normal daily urine output in an adult? | $0.6$ to $1.6$ L. |
| What is the approximate specific gravity of the ultrafiltrate in the Bowman space? | 1.010 |
| Which reagent strip interference is most likely to cause a false-positive protein result? | Highly buffered alkaline urine. |
| Sulfosalicylic acid (SSA) testing for protein is often used to detect which specific protein type ignored by dipsticks? | Globulins (including Bence-Jones protein). |
| Radiographic dye (intravenous contrast) causes a false increase in specific gravity when measured by which method? | Refractometry. |
| What is the normal daily limit for protein excretion in urine? | $150$ mg/day. |
| What is the primary clinical utility of measuring microalbuminuria? | Detection of early renal involvement in diabetes mellitus. |
| What is the standard renal threshold for glucose in the blood? | $165$ to $180$ mg/dL. |
| The glucose oxidase reaction on reagent strips is specific for which sugar? | $\beta$-D-glucose. |
| Which substance is a common cause of false-negative results in glucose, blood, and bilirubin reagent strip tests? | Ascorbic acid (Vitamin C). |
| Which specific ketone body is primarily detected by the sodium nitroprusside reaction? | Acetoacetic acid. |
| In cases of severe ketoacidosis, why might reagent strips underestimate the level of ketosis? | They do not detect $\beta$-hydroxybutyric acid. |
| How can hemoglobinuria be differentiated from myoglobinuria in a urine sample? | Ammonium sulfate precipitation (hemoglobin precipitates, myoglobin remains in supernatant). |
| The reagent strip blood test is based on the _____ activity of hemoglobin. | Pseudoperoxidase. |
| Which form of bilirubin is the only one capable of appearing in urine? | Conjugated bilirubin. |
| Which reagent is used in the Ehrlich reaction to detect urobilinogen? | p-dimethylaminobenzaldehyde. |
| At what time of day is urobilinogen excretion typically at its highest? | Midafternoon (diurnal variation). |
| A positive nitrite test on a reagent strip indicates the presence of _____. | Nitrate-reducing bacteria. |
| The leukocyte esterase test detects the presence of which type of cells? | Polymorphonuclear neutrophils (PMNs). |
| Creatinine clearance is primarily used as a measure of _____. | Glomerular filtration rate (GFR). |
| What is the formula for calculating creatinine clearance ($C$)? | $C = \frac{U \times V}{P} \times \frac{1.73}{A}$ |
| Which serum analyte is used as an alternative to creatinine for calculating eGFR because it is not affected by muscle mass? | Cystatin C. |
| A BUN:creatinine ratio of $20:1$ or higher is highly suggestive of which condition? | Prerenal failure. |
| What does the presence of 'orthostatic albuminuria' imply? | Proteinuria that occurs only when the patient is in an erect position. |
| In workplace drug testing, what specific gravity and creatinine levels define a 'dilute' specimen? | SG $< 1.003$ and creatinine $< 20$ mg/dL. |
| What stain is commonly used in urine microscopy to differentiate renal tubular cells from PMNs? | Sternheimer-Malbin stain. |
| Define 'glitter cells' in urinary sediment. | PMNs with granules showing Brownian movement, seen in hypotonic urine. |
| WBC casts in urinary sediment specifically indicate that inflammation or infection originates in the _____. | Kidneys (renal origin). |
| Which epithelial cells found in urine are considered the most clinically significant? | Renal tubular epithelial cells. |
| What are dysmorphic RBCs in urine sediment usually associated with? | Glomerular bleeding (Glomerulonephritis). |
| Oval fat bodies are associated with which renal condition? | Nephrotic syndrome. |
| What is the primary protein component of all urinary casts? | Uromodulin (Tamm-Horsfall protein). |
| The presence of which type of cast signals end-stage renal failure? | Waxy casts (or broad waxy casts). |
| Which crystal is described as a colorless, hexagonal plate and is associated with a metabolic defect? | Cystine. |
| The finding of tyrosine and leucine crystals together in urine is indicative of severe _____. | Liver disease (Cirrhosis). |
| Which crystal is commonly known as the 'thornapple' crystal? | Ammonium biurate. |
| Triple phosphate crystals are typically found in urine with which pH range? | Alkaline or neutral. |
| What is the most common component found in renal calculi (kidney stones)? | Calcium oxalate. |
| Where is cerebrospinal fluid (CSF) primarily formed? | Choroid plexus. |
| What is the term for yellow pigmentation of CSF? | Xanthochromia. |
| In CSF analysis, what does 'pleocytosis' mean? | An increased number of white blood cells. |
| Which CSF findings are characteristic of acute bacterial meningitis? | Increased PMNs, decreased glucose, and increased lactate. |
| The presence of oligoclonal bands in CSF electrophoresis is a diagnostic indicator for _____. | Multiple Sclerosis (MS). |
| Which protein, found in CSF but not in serum, is used to identify CSF leakage (rhinorrhea)? | $\beta$-transferrin (tau protein). |
| How are serous effusions classified based on the mechanism of accumulation? | Transudates or Exudates. |
| A fluid-to-serum total protein ratio greater than $0.5$ is characteristic of a(n) _____. | Exudate. |
| Which crystal is the primary cause of gouty arthritis? | Monosodium urate (Uric acid). |
| Which crystal is associated with 'pseudogout'? | Calcium pyrophosphate. |
| Under polarized light with a red compensator, uric acid crystals appear _____ when parallel to the slow axis. | Yellow. |
| Amniotic fluid bilirubin is measured at which wavelength to assess fetal hemolytic disease? | $450$ nm. |
| An L/S ratio of _____ or greater usually indicates fetal lung maturity. | $2:1$ |
| What is the clinical significance of phosphatidylglycerol (PG) in amniotic fluid? | Its presence indicates fetal lung maturity, even if the L/S ratio is low. |
| The 'hook effect' in hCG assays leads to what type of error? | Falsely low results in cases of extreme antigen excess. |
| In maternal screening, a decrease in AFP and estriol with an increase in hCG and inhibin A suggests _____. | Down Syndrome (Trisomy 21). |
| What is the lower reference limit for sperm concentration according to standard semen analysis? | $15$ million per mL. |
| Which carbohydrate is the primary nutrient source for sperm motility in seminal fluid? | Fructose. |
| Zollinger-Ellison syndrome is characterized by an overproduction of which hormone? | Gastrin. |
| The xylose absorption test is used to differentiate pancreatic insufficiency from _____. | Malabsorption syndrome. |
| Which fecal enzyme is the most sensitive and specific for detecting chronic pancreatitis? | Fecal elastase-1. |
