CMT CMT Urinalysis and Body Fluids 2 — Questions and Answers
Question 1: In a cerebrospinal fluid (CSF) analysis, a markedly elevated protein with normal glucose most likely indicates:
- Bacterial meningitis
- Viral meningitis
- Guillain-Barré syndrome (Correct answer)
- Fungal meningitis
Correct answer: Guillain-Barré syndrome
Guillain-Barré syndrome classically presents with albuminocytologic dissociation: very high CSF protein with a normal cell count and normal glucose.
Question 2: Which finding in CSF is most consistent with bacterial meningitis?
- Decreased protein, increased glucose, lymphocytosis
- Increased protein, decreased glucose, neutrophilia (Correct answer)
- Normal protein, normal glucose, RBCs
- Increased protein, normal glucose, eosinophilia
Correct answer: Increased protein, decreased glucose, neutrophilia
Bacterial meningitis typically causes elevated CSF protein, reduced glucose (bacteria consume it), and a predominance of neutrophils.
Question 3: Xanthochromia of CSF refers to:
- Turbid, white appearance
- Yellow or orange discoloration (Correct answer)
- Pink tint from fresh blood
- Clear colorless fluid
Correct answer: Yellow or orange discoloration
Xanthochromia is the yellow or orange pigmentation of CSF due to hemoglobin breakdown products (oxyhemoglobin, bilirubin) after subarachnoid hemorrhage.
Question 4: When differentiating a traumatic tap from true subarachnoid hemorrhage, which finding supports subarachnoid hemorrhage?
- Decreasing RBC count in successive tubes
- Uniform RBC count across all tubes (Correct answer)
- Clot formation in the collection tube
- Clear supernatant after centrifugation
Correct answer: Uniform RBC count across all tubes
In subarachnoid hemorrhage, blood is uniformly distributed throughout all CSF collection tubes, while a traumatic tap shows decreasing RBCs in successive tubes.
Question 5: The reference method for synovial fluid crystal identification is:
- Gram stain
- Compensated polarized light microscopy (Correct answer)
- Phase contrast microscopy
- Wright stain
Correct answer: Compensated polarized light microscopy
Compensated polarized light microscopy distinguishes monosodium urate (gout, negatively birefringent) from calcium pyrophosphate (pseudogout, positively birefringent) crystals.
Question 6: A pleural fluid Light's criteria exudate requires LDH greater than what fraction of the upper limit of serum LDH?
- 0.45 (Correct answer)
- 0.60
- 0.50
- 0.35
Correct answer: 0.45
By Light's criteria, a pleural fluid is an exudate if pleural fluid LDH is more than 0.45 times (>2/3 of some sources use 0.67, but the classic ratio threshold is >0.6 for the fluid/serum LDH ratio — the threshold here is 0.45 for the pleural LDH/serum LDH upper-limit ratio), indicating an inflammatory process.
CMT CMT Urinalysis and Body Fluids 2
In a cerebrospinal fluid (CSF) analysis, a markedly elevated protein with normal glucose most likely indicates: