CSMLS CSMLS Urinalysis and Body Fluids 2 — Questions and Answers
Question 1: Glucose in urine (glucosuria) typically appears when blood glucose exceeds the renal threshold of approximately:
- 5.5 mmol/L
- 10 mmol/L (Correct answer)
- 15 mmol/L
- 3.0 mmol/L
Correct answer: 10 mmol/L
Glucosuria occurs when blood glucose exceeds approximately 10 mmol/L (180 mg/dL), saturating the tubular reabsorption capacity.
Question 2: In cerebrospinal fluid (CSF) analysis, xanthochromia (yellow discoloration) indicates:
- Bacterial meningitis
- Previous subarachnoid hemorrhage (Correct answer)
- Viral encephalitis
- Normal finding
Correct answer: Previous subarachnoid hemorrhage
Xanthochromia results from oxyhemoglobin and bilirubin released by lysed red blood cells after subarachnoid hemorrhage.
Question 3: Normal CSF total protein is approximately:
- 0.15–0.45 g/L (Correct answer)
- 1.5–4.5 g/L
- 5–10 g/L
- Less than 0.05 g/L
Correct answer: 0.15–0.45 g/L
Normal CSF total protein ranges from 0.15 to 0.45 g/L, which is much lower than plasma protein levels due to the blood-brain barrier.
Question 4: Pleural fluid with a protein concentration greater than 30 g/L is classified as:
- Transudate
- Exudate (Correct answer)
- Chylous effusion
- Hemothorax
Correct answer: Exudate
Exudates have protein greater than 30 g/L (or LDH-based Light's criteria), indicating inflammation, infection, or malignancy as the cause.
Question 5: Synovial fluid from a patient with gout would typically show:
- Negatively birefringent needle-shaped crystals under polarized light (Correct answer)
- Positively birefringent rhomboid crystals
- No crystals
- Only white blood cells
Correct answer: Negatively birefringent needle-shaped crystals under polarized light
Gout is characterized by negatively birefringent, needle-shaped monosodium urate crystals identified under compensated polarized light microscopy.
Question 6: Proteinuria detected on a urine dipstick is most sensitive for:
- Bence Jones protein
- Albumin (Correct answer)
- Globulins
- Tamm-Horsfall protein
Correct answer: Albumin
The urine dipstick protein reaction uses a pH indicator dye that is most sensitive to albumin and may miss other protein types.
CSMLS CSMLS Urinalysis and Body Fluids 2
Glucose in urine (glucosuria) typically appears when blood glucose exceeds the renal threshold of approximately: