CMLA Urinalysis 3 — Questions and Answers
Question 1: Which reagent strip pad detects leukocyte esterase in urine?
- Glucose oxidase
- Esterase enzyme from granulocytes (Correct answer)
- Copper reduction
- Diazonium salt reaction
Correct answer: Esterase enzyme from granulocytes
Leukocyte esterase pads detect the esterase enzyme released by lysed granulocytes (primarily neutrophils) in urine.
Question 2: Bilirubin in urine produces what characteristic finding when the specimen is shaken?
- White foam
- Yellow foam (Correct answer)
- Pink discoloration
- No foam
Correct answer: Yellow foam
Bilirubin in urine produces a yellow foam when shaken, which helps differentiate it from other causes of yellow discoloration.
Question 3: Which condition would cause false-negative glucose results on a urine dipstick?
- High vitamin C (ascorbic acid) concentration (Correct answer)
- Alkaline urine pH
- Presence of ketones
- High specific gravity
Correct answer: High vitamin C (ascorbic acid) concentration
High ascorbic acid concentrations interfere with the glucose oxidase reaction, causing false-negative dipstick glucose results.
Question 4: What type of cast is associated with end-stage renal disease or chronic renal failure?
- Hyaline cast
- RBC cast
- Waxy cast (Correct answer)
- WBC cast
Correct answer: Waxy cast
Waxy casts form from degenerated granular casts in dilated, damaged tubules and are associated with severe chronic renal disease.
Question 5: A first-morning urine specimen is preferred for pregnancy tests because:
- It has the highest concentration of hCG (Correct answer)
- It is the most sterile specimen
- It has the lowest pH
- It contains the most glucose
Correct answer: It has the highest concentration of hCG
First-morning urine contains the highest concentration of hCG due to overnight accumulation, improving test sensitivity.
Question 6: Which urine crystal is seen in patients with cystinuria and appears as hexagonal plates?
- Uric acid
- Calcium oxalate
- Cystine (Correct answer)
- Triple phosphate
Correct answer: Cystine
Cystine crystals form colorless hexagonal plates and are pathological, indicating cystinuria, an inherited amino acid disorder.
Question 7: The urine dipstick protein test primarily detects which protein?
- Globulin
- Bence Jones protein
- Albumin (Correct answer)
- Fibrinogen
Correct answer: Albumin
The dipstick protein pad uses the protein error of indicators principle and is most sensitive to albumin.
CMLA Urinalysis 3
Which reagent strip pad detects leukocyte esterase in urine?