MLT GlobeUrinalysis & Body Fluids: Other body fluids (synovial, serous, semen, amniotic, fecal) – page 3
71 Urinalysis & Body Fluids MCQs on Other body fluids (synovial, serous, semen, amniotic, fecal) with answers and explanations.
A patient has severe chest pain after repeated vomiting. Left pleural fluid has a very high amylase, a low pH and food particles. The most likely cause is:
Salivary amylase and gastric contents leak into the pleural space through an oesophageal tear. Pancreatitis also raises pleural amylase, but food particles point to oesophageal rupture.
Bloody pleural fluid has a haematocrit of 22%, and the blood haematocrit is 38%. This most likely indicates:
A fluid haematocrit greater than 50% of the blood haematocrit (here 58%) defines a haemothorax. A traumatic tap gives much less blood, and its amount falls as the tap continues.
Pleural fluid contains more than 10% eosinophils. Which is the most common cause?
Pneumothorax and haemothorax are the most frequent causes of pleural eosinophilia; allergy, parasites and some drugs are others. Tuberculous effusions are usually lymphocytic.
Which condition is most likely to produce ascites with a low serum–ascites albumin gradient (below 1.1 g/dL or 11 g/L)?
A low gradient means the ascites is not due to portal hypertension, as in peritoneal carcinomatosis, tuberculous peritonitis or pancreatitis. Cirrhosis, heart failure and Budd–Chiari syndrome give a high gradient.
After a pelvic fracture, a patient has new ascites. Ascitic creatinine is much higher than serum creatinine. This most suggests:
Leakage of urine into the peritoneum makes ascitic creatinine (and urea) much higher than serum levels. Pancreatitis raises ascitic amylase instead.
A semen sample is still a thick gel 90 minutes after collection at body temperature. Deficient secretion from which gland most likely explains this?
Semen coagulates due to seminal vesicle proteins and liquefies through prostatic proteases such as PSA. Liquefaction not complete by 60 minutes suggests prostatic dysfunction.
According to the WHO 2021 manual, what is the lower reference limit (5th centile) for semen volume?
WHO 2021 gives 1.4 mL as the 5th centile of volume in fertile men. Low volume may mean incomplete collection, obstruction or retrograde ejaculation.
According to the WHO 2021 manual, what is the lower reference limit for progressive sperm motility?
The 5th centile is 30% for progressive motility and 42% for total motility (progressive plus non-progressive). 4% is the limit for normal forms.
Using strict (Tygerberg) criteria, what is the WHO 2021 lower reference limit for sperm with normal morphology?
The WHO 2021 5th centile for normal forms by strict (Tygerberg) criteria is 4%. 54% is the lower limit for vitality, 30% for progressive motility, and 14% was Kruger's older strict-criteria prognostic threshold, not the WHO reference limit.
A semen sample has volume 3.0 mL and sperm concentration 10 × 10⁶/mL. Using WHO 2021 limits, the total sperm number is:
Total number = concentration × volume = 10 × 3.0 = 30 × 10⁶, which is below the WHO 2021 lower limit of 39 × 10⁶ per ejaculate.
A semen sample contains many round cells. Which test separates leukocytes from immature germ cells?
Neutrophils are peroxidase-positive, while immature germ cells are negative; above 1 × 10⁶ peroxidase-positive cells/mL suggests infection or inflammation. Eosin–nigrosin tests sperm vitality.
A man had a vasectomy 12 weeks ago. Which post-vasectomy semen result allows him to stop other contraception?
Success requires azoospermia or only rare non-motile sperm (below about 100,000/mL); any motile sperm means the procedure has not yet worked. WHO reference limits for fertility do not apply here.
In the qualitative fecal fat test, why is a second slide treated with acetic acid and heat before Sudan III staining?
Fatty acid salts (soaps) do not stain directly; acid and heat change them to free fatty acids that stain orange-red. The direct slide shows neutral fats only.
A patient on a diet containing about 100 g fat per day collects stool for 72 hours. The fecal fat is 18 g/day. The best interpretation is:
On a 100 g/day fat diet, excretion above 7 g/day indicates steatorrhoea from maldigestion or malabsorption. Lactose intolerance is shown by reducing substances, not fecal fat.
A 25-year-old with chronic diarrhoea has fecal calprotectin of 450 µg/g. This result most supports:
Calprotectin comes from neutrophils in the gut wall, so high levels indicate mucosal inflammation such as IBD. Irritable bowel syndrome usually gives normal calprotectin.
For the sweat chloride test, sweating is stimulated by:
Pilocarpine is driven into the skin with a small electric current, causing local sweating that is collected by filter paper or a plastic collection coil. Whole-body heating is unsafe and unstandardised.
Sequential bronchoalveolar lavage aliquots become more bloody, and many macrophages stain positive with Prussian blue. This suggests:
Increasing blood in serial aliquots with haemosiderin-laden macrophages indicates bleeding within the alveoli. Alveolar proteinosis gives milky fluid with PAS-positive material.
Stool microscopy from a patient with bloody diarrhea and fever shows many neutrophils. This most suggests:
Fecal leukocytes indicate inflammation of the intestinal wall, as seen with invasive organisms such as Shigella, Salmonella and Campylobacter. Toxin-mediated and viral diarrheas usually lack them.
A semen sample has normal volume but a sperm concentration of 5 million/mL. How is this described?
A concentration below the WHO lower reference limit (16 million/mL in the 2021 manual) is oligozoospermia. Azoospermia is no sperm, and asthenozoospermia refers to poor motility.
An infant has watery diarrhea after milk feeds, and the stool gives a positive copper-reduction (Clinitest) test for reducing substances. This most suggests:
Unabsorbed sugars such as lactose reach the stool and give a positive reducing substances test, pointing to carbohydrate (e.g. lactase) deficiency.