Exam Prep
Urine collection and physical, chemical and microscopic examination, plus CSF, serous, synovial and amniotic fluids, semen and feces.
Independent practice questions written by Labologics. Not affiliated with DHA, DOH (formerly HAAD), SCFHS, Prometric or any exam body. Not recalled exam questions.
Which urine specimen is preferred for routine bacterial culture?
Answer: A — Midstream clean-catch urine
Cleansing and collecting the middle of the stream reduces contamination from skin and urethral flora.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Which urine collection gives the most sterile specimen?
Answer: B — Suprapubic aspiration
A needle is passed through the abdominal wall into the bladder, avoiding urethral contamination; used mainly in infants.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Why is a first morning urine specimen preferred for pregnancy tests and routine screening?
Answer: C — It is the most concentrated
Overnight concentration increases detection of hCG, protein and formed elements.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
How is a 24-hour urine collection started correctly?
Answer: D — Discard the first morning void, then collect all urine including the next morning's first void
Timing starts after emptying the bladder. 24-hour urine is used for creatinine clearance, protein, catecholamines/metanephrines, copper and ALA.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
If a urine sample cannot be tested within 2 hours, it should be:
Answer: A — Refrigerated at 2-8 C
Refrigeration slows bacterial growth and chemical change. Amorphous crystals may precipitate in the cold.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Which change occurs in unpreserved urine left at room temperature for several hours?
Answer: B — Increased pH and bacteria, decreased glucose
Bacteria convert urea to ammonia (pH rises) and use glucose. Bilirubin breaks down in light, and cells and casts lyse in alkaline dilute urine.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Which preservative is commonly used in urine culture transport tubes?
Answer: C — Boric acid
Boric acid keeps the bacterial count stable for transport; formalin preserves sediment but would kill bacteria.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Red, CLOUDY urine that clears on centrifugation with red cells in the sediment indicates:
Answer: D — Hematuria
Intact red cells cause cloudiness. Clear red urine with a red supernatant after spinning suggests hemoglobin or myoglobin.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Urine that darkens to black on standing, especially in alkaline conditions, suggests:
Answer: A — Alkaptonuria (homogentisic acid)
Melanin (melanoma) can also cause urine to darken to black.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Dark amber urine with yellow foam on shaking suggests:
Answer: B — Bilirubin
Bilirubin gives amber urine with yellow foam; concentrated urine from dehydration is also dark yellow but its foam is white.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
A mousy or musty urine odor in an infant suggests:
Answer: C — Phenylketonuria
Maple syrup odor suggests MSUD (raised leucine, isoleucine, valine); a fruity odor suggests ketones; ammonia odor suggests old urine or urease-producing bacteria.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
The normal range of random urine specific gravity is about:
Answer: D — 1.003-1.035
A fixed SG of about 1.010 (isosthenuria) suggests loss of renal concentrating ability. SG below 1.010 is hyposthenuric, above 1.010 hypersthenuric.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
A urine specific gravity of 1.050 by refractometer, with a much lower reagent strip SG, suggests:
Answer: A — Radiographic contrast media or other high-molecular-weight substances
Physiological urine rarely exceeds about 1.040. Refractometers read contrast media and mannitol; the reagent strip measures ionic solutes only.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Urine and serum osmolality are measured most accurately by:
Answer: B — Freezing point depression osmometry
Osmolality depends on the number of particles; glucose, protein and contrast media affect SG more than osmolality.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
The reagent strip protein test is most sensitive to:
Answer: C — Albumin
It uses the protein error of indicators. Highly alkaline or buffered urine can give a false positive; sulfosalicylic acid (SSA) precipitation detects all proteins.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
An infant has a negative glucose strip but a positive copper reduction (Clinitest) test. This suggests:
Answer: D — A non-glucose reducing sugar such as galactose
Strips use glucose oxidase, which is specific for glucose. Clinitest detects all reducing sugars; galactosemia must be considered in infants.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
A child has strongly positive urine glucose. The FIRST concern is:
Answer: A — Type 1 diabetes mellitus
Check blood glucose and ketones first. Renal glycosuria (normal blood glucose) is diagnosed only after diabetes is excluded.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Ketones in urine with normal glucose are commonly seen in:
Answer: B — Starvation, vomiting or a low-carbohydrate diet
The nitroprusside strip detects acetoacetate (and acetone), not beta-hydroxybutyrate.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
A strip is positive for blood but no red cells are seen on microscopy, and the urine is fresh. Likely causes are:
Answer: C — Hemoglobinuria or myoglobinuria
The test detects the pseudoperoxidase activity of heme. Red cells may also lyse in dilute or alkaline urine.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
The reagent strip test that detects bacteria is:
Answer: D — Nitrite
Gram-negative bacteria reduce nitrate to nitrite. Leukocyte esterase detects neutrophils, not bacteria.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Which can cause a FALSE-NEGATIVE nitrite test?
Answer: A — Infection with Enterococcus, which cannot reduce nitrate
False negatives also occur when urine stays in the bladder less than 4 hours, with low nitrate diet, and with ascorbic acid.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
The leukocyte esterase test does NOT detect:
Answer: B — Lymphocytes
Esterases are present in granulocytes and monocytes but not lymphocytes.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Urine bilirubin positive with urobilinogen absent suggests:
Answer: C — Complete biliary obstruction
No bile reaches the gut, so no urobilinogen forms. Hemolysis gives raised urobilinogen with negative bilirubin.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
A diet rich in vegetables and fruit tends to make urine:
Answer: D — More alkaline
High-protein (meat) diets make urine more acidic. Normal urine pH is about 4.5-8.0.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
A patient has systemic metabolic acidosis but persistently alkaline urine (pH above 5.5). This suggests:
Answer: A — Distal (type 1) renal tubular acidosis
In distal RTA the tubules cannot secrete hydrogen ions, so urine cannot be acidified normally.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
The most common cast in urine, which may be seen in healthy people after exercise, is:
Answer: B — Hyaline cast
Hyaline casts are made of uromodulin (Tamm-Horsfall protein), the matrix of all casts. They have a low refractive index, so use reduced light.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Red blood cell casts indicate:
Answer: C — Glomerular bleeding, e.g., glomerulonephritis
Red cells entered the tubules and were trapped in a cast. Dysmorphic red cells also suggest glomerular origin.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
White blood cell casts with bacteria and pyuria most strongly suggest:
Answer: D — Pyelonephritis
Casts form in the tubules, so WBC casts localize infection or inflammation to the kidney. WBC casts without bacteria suggest interstitial nephritis.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Waxy casts with a high refractive index and cracked edges indicate:
Answer: A — Urinary stasis in chronic renal failure
They represent advanced cast degeneration. Broad casts form in dilated tubules and also suggest end-stage renal disease.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Oval fat bodies and fatty casts showing a Maltese cross under polarized light suggest:
Answer: B — Nephrotic syndrome
Cholesterol esters give the Maltese cross pattern.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Envelope-shaped crystals in acidic urine are:
Answer: C — Calcium oxalate dihydrate
Oval or dumbbell monohydrate calcium oxalate crystals are linked to ethylene glycol poisoning.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Colorless 'coffin lid' crystals in alkaline urine are:
Answer: D — Triple phosphate (magnesium ammonium phosphate)
They are linked to urease-producing bacteria such as Proteus and struvite stones.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Yellow-brown rhombic or diamond-shaped crystals in acidic urine are:
Answer: A — Uric acid
Uric acid crystals increase with gout, high purine turnover and chemotherapy.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
A pink 'brick dust' sediment in refrigerated acidic urine is most likely:
Answer: B — Amorphous urates
Amorphous urates (acidic urine) dissolve on warming; amorphous phosphates (alkaline urine) form a white precipitate and dissolve in acetic acid.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Colorless hexagonal crystals in acidic urine suggest an inherited disorder of amino acid transport. They are:
Answer: C — Cystine
Cystinuria causes cystine stones; confirm with the cyanide-nitroprusside test. Leucine and tyrosine crystals suggest severe liver disease.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Red cells in very dilute (hypotonic) urine swell and lose hemoglobin, appearing as:
Answer: D — Ghost cells
Glitter cells are neutrophils with Brownian motion of granules in dilute urine.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Many squamous epithelial cells in a urine sample usually indicate:
Answer: A — Contamination from the vagina or skin (poor collection)
Transitional epithelial cells come from the bladder and renal pelvis. Renal tubular epithelial cells are the most significant, indicating tubular damage.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
How can yeast be distinguished from red cells in urine sediment?
Answer: B — Yeast cells are budding and oval and do not lyse in 2% acetic acid
Acetic acid lyses red cells but not yeast. Look for budding and pseudohyphae.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Heavy proteinuria, edema, oval fat bodies and fatty casts indicate:
Answer: C — Nephrotic syndrome
Serum albumin is low and lipids are high.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Positive nitrite and leukocyte esterase with bacteria and WBCs on microscopy. The next step is:
Answer: D — Urine culture and sensitivity
A significant colony count is usually 10^5 CFU/mL or more in a midstream sample (lower counts can matter in symptomatic patients or catheter samples).
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
A woman's urine has many red cells but is otherwise normal, and she is menstruating. The best action is:
Answer: A — Note possible menstrual contamination and repeat after menstruation
Kidney stones cause hematuria with flank pain; exercise can also cause transient hematuria.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Three CSF tubes are collected. Tube 1 is used for chemistry and serology. Tube 3 is usually used for:
Answer: B — Cell count
Tube 2 goes to microbiology. Tube 3 is least affected by blood introduced during the tap.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
CSF with many neutrophils, low glucose and high protein suggests:
Answer: C — Bacterial meningitis
Viral meningitis typically shows lymphocytes with normal glucose. Tuberculous and fungal meningitis show lymphocytes with low glucose.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
CSF is equally bloody in tubes 1, 2 and 3, and the supernatant is xanthochromic. This suggests:
Answer: D — Subarachnoid hemorrhage
In a traumatic tap, blood decreases from tube 1 to tube 3 and the supernatant is clear.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Using Light's criteria, a pleural fluid is an exudate if:
Answer: A — Fluid/serum protein ratio is above 0.5 or fluid/serum LD ratio is above 0.6
Exudates (infection, malignancy, inflammation) have high protein and LD; transudates (heart failure, cirrhosis) are low.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Needle-shaped crystals with strong NEGATIVE birefringence in synovial fluid indicate:
Answer: B — Gout (monosodium urate)
MSU crystals appear yellow when aligned parallel to the compensator. CPPD crystals are rhomboid and weakly positively birefringent (blue when parallel).
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Ragocytes (neutrophils with dark cytoplasmic inclusions) in synovial fluid are associated with:
Answer: C — Rheumatoid arthritis
They contain immune complexes, including rheumatoid factor.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Fetal lung maturity is indicated by a lecithin/sphingomyelin (L/S) ratio of:
Answer: D — 2.0 or higher, with phosphatidylglycerol present
Phosphatidylglycerol is a reliable maturity marker and is not affected by blood or meconium contamination.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
If the first portion of an ejaculate is lost during collection, the result is likely to show:
Answer: A — Falsely low sperm count
The first fraction is the most sperm-rich. Collect after 2-7 days of abstinence and deliver within 1 hour, kept near body temperature.
Reference: WHO Laboratory Manual for the Examination and Processing of Human Semen (6th ed., 2021)
In the eosin-nigrosin vitality stain:
Answer: B — Dead sperm stain pink; live sperm stay unstained against a dark background
Dead cells have damaged membranes that let eosin in; nigrosin gives the dark background.
Reference: WHO Laboratory Manual for the Examination and Processing of Human Semen (6th ed., 2021)
A sperm concentration below the WHO lower reference limit is called:
Answer: C — Oligozoospermia
WHO 2021 lower reference limit for concentration is 16 million/mL. Azoospermia = no sperm; asthenozoospermia = poor motility; teratozoospermia = abnormal morphology.
Reference: WHO Laboratory Manual for the Examination and Processing of Human Semen (6th ed., 2021)
Steatorrhea (fat in stool) is screened qualitatively with:
Answer: D — Sudan III (or IV) stain
A 72-hour quantitative fecal fat is the definitive test. Fecal elastase assesses pancreatic insufficiency.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids
Which occult blood test is specific for human hemoglobin and not affected by diet?
Answer: A — Immunochemical test (FIT)
Guaiac tests react with peroxidase activity, so red meat and some vegetables can give false positives.
Reference: Strasinger & Di Lorenzo: Urinalysis and Body Fluids