MLT GlobeUrinalysis & Body Fluids: Other body fluids (synovial, serous, semen, amniotic, fecal) – page 4
71 Urinalysis & Body Fluids MCQs on Other body fluids (synovial, serous, semen, amniotic, fecal) with answers and explanations.
Which anticoagulant is preferred for a synovial fluid tube used for crystal examination?
Sodium heparin is preferred; lithium heparin, powdered EDTA and oxalate can form crystals that may be mistaken for pathological ones.
Pleural fluid pH is requested for a parapneumonic effusion. Which handling is correct?
Air exposure lets CO2 escape and raises pH, so the sample must be anaerobic and measured with a blood gas analyser. A pH below 7.2 suggests a complicated effusion needing drainage.
A man has azoospermia, semen volume 0.6 mL, acidic pH and absent fructose. The most likely cause is:
Fructose and most semen volume come from the seminal vesicles; their absence or obstruction gives low-volume, acidic, fructose-negative semen with no sperm. Testicular failure gives normal volume and fructose.
Amniotic fluid lamellar body count is used to assess fetal lung maturity. How is it usually measured?
Lamellar bodies, which store surfactant, are similar in size to platelets and are counted on the platelet channel. Thin-layer chromatography is used for the L/S ratio, and 450 nm for bilirubin.
A synovial fluid shows small clumps that are not birefringent under polarised light but stain red with alizarin red S. These are most likely:
Hydroxyapatite crystals are too small to see singly and are non-birefringent; alizarin red S stains calcium-containing clumps. Urate crystals are strongly birefringent needles.
A milky pleural effusion from a patient with long-standing tuberculous pleurisy has cholesterol 280 mg/dL (7.2 mmol/L), triglyceride 30 mg/dL (0.34 mmol/L) and cholesterol crystals. This is best classified as:
High cholesterol with low triglyceride and cholesterol crystals in a chronic effusion is pseudochylous. A true chylous effusion has triglyceride above 110 mg/dL and chylomicrons.
A heart-failure patient on diuretics has a pleural effusion that just meets an exudate criterion. Which finding best supports that it is really a transudate?
Diuretics concentrate pleural protein and LD; a serum–pleural albumin gradient above 1.2 g/dL (12 g/L) indicates a transudate. Very high LD and low pH point to an exudate such as empyema.
A man with diabetes has a semen volume of 0.3 mL with no sperm. A urine sample passed just after ejaculation contains many sperm. The most likely cause is:
In retrograde ejaculation, often due to diabetic neuropathy, semen passes into the bladder, so sperm appear in post-ejaculatory urine. With absent vas deferens or testicular failure, urine would not contain sperm.
In a pregnancy with maternal diabetes, the amniotic L/S ratio is 2.1. Which additional finding best confirms fetal lung maturity?
In diabetic pregnancies the L/S ratio can reach 2.0 while the lungs remain immature; phosphatidylglycerol appears later and confirms maturity. The fern test identifies amniotic fluid, not lung maturity.
Stool water from a patient with watery diarrhoea has sodium 30 mmol/L and potassium 40 mmol/L. Using an osmolality of 290 mOsm/kg, the fecal osmotic gap and likely diarrhoea type are:
Gap = 290 − 2(30 + 40) = 150 mOsm/kg. A large gap (above about 100–125) means unmeasured solutes such as poorly absorbed sugars or laxatives, indicating osmotic diarrhoea. Secretory diarrhoea has a gap below 50.
Bronchoalveolar lavage from a patient with hilar lymphadenopathy shows 35% lymphocytes with a CD4:CD8 ratio of 5. This most suggests:
Lymphocytosis with a CD4:CD8 ratio above 3.5 strongly supports sarcoidosis. Hypersensitivity pneumonitis also causes lymphocytosis but usually with a low CD4:CD8 ratio.