Rivalta's test on a body fluid is used to tell:

Urate from pyrophosphate crystals

Bacterial from viral meningitis

Why must CSF for glucose be tested promptly or preserved with fluoride?

Cells and bacteria in it consume glucose

Glucose rises as cells break down

Fluoride stops the CSF from clotting

Light destroys glucose in the sample

Clinical pathology: CSF and body fluids

26 Kerala PSC Lab Technician Gr II practice questions on Clinical pathology: CSF and body fluids, part of Pathology. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Easy
Rivalta's test on a body fluid is used to tell:
1. AUrate from pyrophosphate crystals
2. BExudate from transudate
3. CChyle from pseudochyle
4. DBacterial from viral meningitis
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Answer: B · Exudate from transudate
A drop of the fluid is let fall into water containing a little glacial acetic acid. An exudate, rich in protein and fibrinogen, leaves a white, cloud-like trail as it sinks, while a transudate mixes in and disappears. It is a simple bedside screen; protein and LDH ratios (Light's criteria) give a firmer answer. Exudates arise from inflammation, infection or tumour, transudates from heart failure, cirrhosis or nephrotic syndrome.
- A: Crystals are identified by polarising microscopy, not Rivalta's test.
- C: Chylous and pseudochylous fluids are told apart by ether clearing and fat stains.
- D: Bacterial and viral meningitis are told apart by CSF cells, glucose and protein.
Question 2 · Medium
Which cause of ascites gives a serum-ascites albumin gradient (SAAG) of 1.1 g/dL or more?
1. APancreatitis
2. BPortal hypertension
3. CTuberculous peritonitis
4. DPeritoneal carcinomatosis
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Answer: B · Portal hypertension
SAAG = serum albumin minus ascitic fluid albumin, measured on samples taken the same day. A gradient of 1.1 g/dL or more means a high hydrostatic pressure in the portal system, as in cirrhosis, heart failure or Budd-Chiari syndrome. A gradient below 1.1 g/dL points to peritoneal causes such as tuberculosis, malignancy or pancreatitis. SAAG separates the causes better than the older transudate-exudate protein cut-off.
- A: Pancreatic ascites gives a low gradient with a very high fluid amylase.
- C: Tuberculous peritonitis inflames the peritoneum and gives a gradient below 1.1 g/dL.
- D: Peritoneal carcinomatosis gives a low gradient, below 1.1 g/dL.
Question 3 · Medium
Why must CSF for glucose be tested promptly or preserved with fluoride?
1. AGlucose rises as cells break down
2. BCells and bacteria in it consume glucose
3. CFluoride stops the CSF from clotting
4. DLight destroys glucose in the sample
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Answer: B · Cells and bacteria in it consume glucose
White cells and bacteria in CSF keep using glucose by glycolysis after collection, so a delayed test can give a falsely low value and suggest bacterial meningitis. Sodium fluoride blocks the glycolytic enzyme enolase and keeps the glucose stable. CSF glucose is always judged against a blood glucose taken at the same time; it is normally about 60-70% of the blood level. Turbid, cell-rich samples lose glucose fastest.
- A: Glucose falls, not rises, on standing.
- C: Fluoride is used here as a glycolysis inhibitor, not to prevent clotting.
- D: Light does not destroy glucose; bilirubin is the light-sensitive analyte.
Question 4 · Hard
Undiluted CSF from a 20-year-old with headache is loaded into a Fuchs-Rosenthal chamber (ruled area 16 mm², depth 0.2 mm). A total of 48 cells are counted over the whole ruled area. The cell count is:
1. A154 cells/µL
2. B3 cells/µL
3. C15 cells/µL
4. D30 cells/µL
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Answer: C · 15 cells/µL
Cells per µL = cells counted ÷ volume counted, with no dilution factor here. The volume over the whole ruled area is 16 mm² × 0.2 mm = 3.2 mm³ (µL), so 48 ÷ 3.2 = 15 cells/µL. The deeper, larger chamber holds more fluid than a Neubauer chamber, which improves precision for the low counts of CSF. A count of 15/µL is above the adult normal of 0-5 cells/µL.
- A: 154 cells/µL multiplies by the volume instead of dividing by it.
- B: 3 cells/µL divides by the area alone and leaves out the depth.
- D: 30 cells/µL uses a depth of 0.1 mm, the depth of a Neubauer chamber.
Question 5 · Easy
A fine cobweb clot forming in CSF left to stand for some hours suggests:
1. ASubarachnoid hemorrhage
2. BPyogenic meningitis
3. CViral meningitis
4. DTuberculous meningitis
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Answer: D · Tuberculous meningitis
In tuberculous meningitis the CSF is clear or slightly hazy, with a raised protein and fibrinogen. On standing, often overnight, a fine pellicle or cobweb clot forms; it traps bacilli, so a smear of the clot is the best material for an AFB stain. Pyogenic meningitis gives turbid CSF that may form a coarse clot. Normal CSF does not clot because it contains almost no fibrinogen.
- A: Subarachnoid hemorrhage gives evenly blood-stained CSF with a yellow supernatant.
- B: Pyogenic meningitis gives turbid CSF that may form a coarse clot, not a fine web.
- C: Viral meningitis has only a slight protein rise, and the CSF does not usually clot.
Question 6 · Medium
What does a poor, friable mucin clot indicate when synovial fluid is added to dilute acetic acid?
1. ABlood contamination during the tap
2. BNormal, highly viscous joint fluid
3. CNon-inflammatory osteoarthritis
4. DInflammatory breakdown of hyaluronic acid
Answer and explanation in LearnFree account
Question 7 · Easy
Needle-shaped crystals with strong negative birefringence in synovial fluid indicate:
1. ARheumatoid arthritis
2. BGout
3. CPseudogout
4. DSeptic arthritis
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Question 8 · Hard
A 2-year-old has fever, neck stiffness and seizures. CSF is turbid: cells 2,400/µL with 90% neutrophils, protein 260 mg/dL (reference 15-45), glucose 18 mg/dL with blood glucose 110 mg/dL. The most likely diagnosis is:
1. AViral meningitis
2. BTuberculous meningitis
3. CAcute bacterial meningitis
4. DSubarachnoid hemorrhage
Answer and explanation in LearnFree account
Question 9 · Easy
Normal CSF glucose is about what proportion of the blood glucose?
1. ATwice as much
2. BTwo-thirds
3. CEqual to it
4. DOne-tenth
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Question 10 · Medium
How does blood from a traumatic lumbar tap behave in the serially collected CSF tubes?
1. AHas a yellow supernatant in each tube
2. BIncreases from the first to the last tube
3. CIs evenly mixed in all the tubes
4. DDecreases from the first to the last tube
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Question 11 · Medium
A milky pleural fluid from a man with lymphoma stays milky after high-speed centrifugation, stains with Sudan III and has triglycerides of 250 mg/dL. It is best described as:
1. APseudochylous effusion
2. BChylous effusion
3. CHemothorax
4. DEmpyema
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Question 12 · Easy
What is the yellow colouring of the CSF supernatant after centrifugation called?
1. AXanthochromia
2. BPellicle formation
3. COpalescence
4. DPleocytosis
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Question 13 · Medium
Why should a CSF cell count be done within one hour of collection?
1. ACells break down on standing
2. BBacteria grow and add to the count
3. CGlucose is used up by the cells
4. DProtein clots and traps cells
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Question 14 · Medium
A 40-year-old has had weakness rising up both legs for two weeks after a diarrheal illness. CSF shows protein 180 mg/dL with 2 cells/µL. This finding is called:
1. ALymphocytic pleocytosis
2. BXanthochromia of the supernatant
3. CFroin's syndrome of spinal block
4. DAlbuminocytological dissociation
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Question 15 · Medium
A 25-year-old has had fever and headache for three weeks. CSF is clear with a fine clot on standing. Which other CSF pattern fits tuberculous meningitis?
1. ALymphocytes raised, protein high, glucose low
2. BCells normal, protein high, glucose normal
3. CLymphocytes raised, protein normal, glucose normal
4. DNeutrophils raised, protein high, glucose very low
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Question 16 · Easy
By Light's criteria, a pleural fluid is an exudate when its fluid-to-serum protein ratio is more than:
1. A0.2
2. B0.6
3. C0.5
4. D1.0
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Question 17 · Hard
Pleural fluid: protein 2.0 g/dL, LDH 180 U/L. Serum: protein 6.5 g/dL, LDH 400 U/L; upper reference limit of serum LDH 240 U/L. By Light's criteria, the fluid is:
1. ATransudate, as both ratios are low
2. BExudate, by the LDH upper-limit criterion
3. CTransudate, as protein is below 3 g/dL
4. DExudate, by the protein ratio
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Question 18 · Easy
How many white cells per µL does normal adult CSF contain?
1. A0-5
2. B20-50
3. C100-200
4. D500-1,000
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Question 19 · Easy
Rhomboid crystals with weak positive birefringence in synovial fluid are typical of:
1. ASeptic arthritis
2. BGout
3. CPseudogout
4. DRheumatoid arthritis
Answer and explanation in LearnFree account
Question 20 · Easy
What is the appearance of normal synovial fluid?
1. AYellow, turbid and watery
2. BMilky white and thick
3. CColourless, clear and watery
4. DPale yellow, clear and highly viscous
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Question 21 · Hard
A 45-year-old has a hot, swollen right knee with fever for two days. Synovial fluid: yellow-green and turbid, low viscosity, WBC 85,000/µL with 95% neutrophils, glucose 20 mg/dL (blood 100 mg/dL), no crystals under polarized light. Most likely diagnosis:
1. AOsteoarthritis
2. BSeptic arthritis
3. CPseudogout
4. DGout
Answer and explanation in LearnFree account
Question 22 · Easy
Normal total protein of lumbar CSF in adults is about:
1. A15-45 mg/dL
2. B6-8 g/dL
3. C150-450 mg/dL
4. D1-4 mg/dL
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Question 23 · Medium
Which condition typically produces a transudative pleural effusion?
1. ATuberculosis
2. BCongestive heart failure
3. CPneumonia
4. DBronchogenic carcinoma
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Question 24 · Medium
In a patient with cirrhosis and fever, an ascitic fluid neutrophil count above 250/µL most likely indicates:
1. AUncomplicated portal hypertension
2. BMalignant ascites
3. CSpontaneous bacterial peritonitis
4. DTuberculous peritonitis
Answer and explanation in LearnFree account
Question 25 · Easy
An India ink preparation of CSF is made to detect:
1. AToxoplasma gondii
2. BCryptococcus neoformans
3. CNeisseria meningitidis
4. DMycobacterium tuberculosis
Answer and explanation in LearnFree account

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Clinical pathology: CSF and body fluids

Rivalta's test on a body fluid is used to tell:

Which cause of ascites gives a serum-ascites albumin gradient (SAAG) of 1.1 g/dL or more?

Why must CSF for glucose be tested promptly or preserved with fluoride?

Undiluted CSF from a 20-year-old with headache is loaded into a Fuchs-Rosenthal chamber (ruled area 16 mm², depth 0.2 mm). A total of 48 cells are counted over the whole ruled area. The cell count is:

A fine cobweb clot forming in CSF left to stand for some hours suggests:

What does a poor, friable mucin clot indicate when synovial fluid is added to dilute acetic acid?

Needle-shaped crystals with strong negative birefringence in synovial fluid indicate:

A 2-year-old has fever, neck stiffness and seizures. CSF is turbid: cells 2,400/µL with 90% neutrophils, protein 260 mg/dL (reference 15-45), glucose 18 mg/dL with blood glucose 110 mg/dL. The most likely diagnosis is:

Normal CSF glucose is about what proportion of the blood glucose?

How does blood from a traumatic lumbar tap behave in the serially collected CSF tubes?

A milky pleural fluid from a man with lymphoma stays milky after high-speed centrifugation, stains with Sudan III and has triglycerides of 250 mg/dL. It is best described as:

What is the yellow colouring of the CSF supernatant after centrifugation called?

Why should a CSF cell count be done within one hour of collection?

A 40-year-old has had weakness rising up both legs for two weeks after a diarrheal illness. CSF shows protein 180 mg/dL with 2 cells/µL. This finding is called:

A 25-year-old has had fever and headache for three weeks. CSF is clear with a fine clot on standing. Which other CSF pattern fits tuberculous meningitis?

By Light's criteria, a pleural fluid is an exudate when its fluid-to-serum protein ratio is more than:

Pleural fluid: protein 2.0 g/dL, LDH 180 U/L. Serum: protein 6.5 g/dL, LDH 400 U/L; upper reference limit of serum LDH 240 U/L. By Light's criteria, the fluid is:

How many white cells per µL does normal adult CSF contain?

Rhomboid crystals with weak positive birefringence in synovial fluid are typical of:

What is the appearance of normal synovial fluid?

A 45-year-old has a hot, swollen right knee with fever for two days. Synovial fluid: yellow-green and turbid, low viscosity, WBC 85,000/µL with 95% neutrophils, glucose 20 mg/dL (blood 100 mg/dL), no crystals under polarized light. Most likely diagnosis:

Normal total protein of lumbar CSF in adults is about:

Which condition typically produces a transudative pleural effusion?

In a patient with cirrhosis and fever, an ascitic fluid neutrophil count above 250/µL most likely indicates:

An India ink preparation of CSF is made to detect: