MLT GlobeUrinalysis & Body Fluids: Other body fluids (synovial, serous, semen, amniotic, fecal) – page 2
71 Urinalysis & Body Fluids MCQs on Other body fluids (synovial, serous, semen, amniotic, fecal) with answers and explanations.
Fecal occult blood testing is used mainly to screen for:
Colorectal cancers and large polyps bleed intermittently in small amounts, so testing stool for hidden blood is used as a screening test.
Amniotic fluid is collected by which procedure?
Amniocentesis is transabdominal needle aspiration of amniotic fluid from the amniotic sac, used for genetic and fetal testing.
Dark green amniotic fluid most likely indicates the presence of:
Meconium (fetal stool) gives amniotic fluid a dark green colour and can indicate fetal distress. Bilirubin gives a yellow colour and blood a red colour.
Synovial fluid from a painful big toe contains needle-shaped crystals. With a red compensator, they are yellow when parallel to the slow axis. These crystals are:
Monosodium urate crystals of gout are needle-shaped and strongly negatively birefringent: yellow when parallel to the slow axis. CPPD crystals appear blue in that position.
Synovial fluid from an elderly patient's knee shows rhomboid, weakly birefringent crystals that are blue when parallel to the slow axis of the compensator. The diagnosis is:
CPPD crystals are rhomboid or rod-shaped with weak positive birefringence (blue when parallel). They are typical of pseudogout, often in the knee of older people.
A synovial fluid is cloudy yellow-green with WBC 85,000/µL (95% neutrophils) and glucose much lower than blood glucose. The most likely classification is:
Very high WBC counts (usually above 50,000/µL) with mostly neutrophils and low glucose indicate septic arthritis; Gram stain and culture are urgent. Noninflammatory fluid has fewer than 2000 WBC/µL.
Pleural fluid protein is 3.5 g/dL and serum protein is 6.0 g/dL. Using Light's criteria (protein ratio >0.5), the fluid is:
Ratio = 3.5 ÷ 6.0 = 0.58, which is above 0.5, so the fluid is an exudate. Only one Light's criterion needs to be met.
Serum albumin is 3.0 g/dL and ascitic fluid albumin is 1.2 g/dL. The serum–ascites albumin gradient and its meaning are:
SAAG = serum albumin − ascitic albumin = 3.0 − 1.2 = 1.8 g/dL. A gradient of 1.1 g/dL or more indicates portal hypertension, such as cirrhosis.
A milky pleural fluid after chest trauma has triglyceride 250 mg/dL (2.8 mmol/L). This fluid is most likely:
Triglyceride above 110 mg/dL (1.24 mmol/L) and chylomicrons indicate chylous effusion from thoracic duct damage. Pseudochylous fluid is rich in cholesterol with low triglyceride.
A lymphocytic pleural exudate from a young patient in a high-prevalence country has markedly raised adenosine deaminase (ADA). This most suggests:
High pleural ADA with lymphocyte predominance strongly supports tuberculous pleurisy, especially where TB is common. Heart failure causes a transudate with low ADA.
A patient with cirrhotic ascites develops fever. Which ascitic fluid finding is diagnostic of spontaneous bacterial peritonitis?
An ascitic neutrophil count of at least 250 cells/µL establishes spontaneous bacterial peritonitis even before culture results. SAAG reflects portal hypertension, not infection.
According to the WHO 2021 manual, the lower reference limit for sperm concentration is:
WHO 2021 gives 16 × 10⁶/mL as the 5th percentile for sperm concentration. The value 39 million is the lower limit for total sperm number per ejaculate, not concentration.
In the eosin–nigrosin vitality test, which appearance indicates a dead sperm?
Dead sperm have damaged membranes and take up eosin, so the head stains pink-red; live sperm exclude the dye and appear white against the dark nigrosin background.
Which is an advantage of the fecal immunochemical test (FIT) over the guaiac fecal occult blood test?
FIT uses antibodies to human globin, so diet (red meat, peroxidase-rich vegetables) does not cause false positives. Globin is digested in the upper GI tract, so FIT detects mainly lower GI bleeding.
A patient with chronic diarrhoea, weight loss and bulky stools has fecal elastase-1 of 80 µg/g stool. This result suggests:
Fecal elastase-1 below about 200 µg/g (and especially below 100 µg/g) indicates exocrine pancreatic insufficiency. Elastase is stable in the gut, so it reflects pancreatic output.
Which diluent should NOT be used for a manual WBC count on synovial fluid?
Acetic acid precipitates hyaluronate-protein complexes (a mucin clot), trapping cells and giving false results. Saline, hypotonic saline or saponin can be used, the last two to lyse red cells.
A synovial fluid is so viscous that it cannot be pipetted accurately for a cell count. What is the recommended pretreatment?
Hyaluronidase breaks down hyaluronic acid and lowers viscosity without damaging cells. Acetic acid forms a mucin clot, and counting supernatant would miss the cells.
In synovial fluid from rheumatoid arthritis, neutrophils with dark cytoplasmic granules containing immune complexes are called:
Ragocytes contain ingested immune complexes (including rheumatoid factor) that look like dark granules. Reiter cells are macrophages that have ingested neutrophils.
A sexually active 22-year-old has migratory joint pain, tenosynovitis and skin pustules. A knee aspirate is sent for culture. Which organism is suspected, and on which medium should it be plated promptly?
This is the arthritis–dermatitis syndrome of disseminated gonococcal infection. N. gonorrhoeae is fastidious, so the fluid should be plated quickly on chocolate agar, avoiding refrigeration.
Pleural fluid LD is 300 U/L and serum LD is 250 U/L. Using Light's criteria, how is the fluid classified?
300/250 = 1.2, which is greater than 0.6, so the fluid meets an LD criterion for an exudate. Meeting any one of Light's criteria is enough.