Medical Laboratory Technician Urinalysis and Body Fluids Questions and Answers — Questions and Answers
Question 1: A technologist examining a urine sediment under a microscope observes numerous small, round, colorless structures. Some of these structures appear to be budding. Which of the following actions would best differentiate yeast from red blood cells?
- Perform a Gram stain on the sediment.
- Add a drop of dilute acetic acid to the sediment. (Correct answer)
- Re-examine the sample using a polarizing microscope.
- Check the reagent strip for a positive protein result.
Correct answer: Add a drop of dilute acetic acid to the sediment.
Adding dilute acetic acid will lyse red blood cells due to their lack of a cell wall, while the rigid cell wall of yeast will remain intact. This allows for clear differentiation when the two are similar in appearance.
Question 2: A cerebrospinal fluid (CSF) sample is received in the laboratory from a patient with a suspected subarachnoid hemorrhage. After centrifugation, the supernatant appears pale pink-yellow. This coloration is referred to as:
- Pleocytosis
- Hemolysis
- Xanthochromia (Correct answer)
- Pellicle formation
Correct answer: Xanthochromia
Xanthochromia is the term for the pink, orange, or yellow discoloration of CSF supernatant. It is caused by the breakdown of red blood cells and the subsequent release of hemoglobin degradation products like bilirubin, which indicates that bleeding occurred in vivo (e.g., a subarachnoid hemorrhage) rather than from a traumatic tap.
Question 3: A urine reagent strip test is positive for bilirubin. Which of the following is the most appropriate confirmatory test for this finding?
- Urobilinogen test
- Specific gravity measurement
- Sulfosalicylic acid (SSA) test
- Ictotest tablet test (Correct answer)
Correct answer: Ictotest tablet test
The Ictotest is a tablet-based diazo reaction test that is more specific and sensitive for urinary bilirubin than the reagent strip method. It is used to confirm positive bilirubin results and rule out false positives caused by interfering substances.
Question 4: A synovial fluid aspirate from a patient with acute joint pain is examined using compensated polarized light microscopy. The technologist observes strongly birefringent, needle-shaped crystals that appear yellow when aligned parallel to the slow axis of the compensator. These findings are characteristic of:
- Cholesterol crystals
- Calcium pyrophosphate dihydrate (CPPD) crystals
- Monosodium urate (MSU) crystals (Correct answer)
- Corticosteroid crystals
Correct answer: Monosodium urate (MSU) crystals
Monosodium urate (MSU) crystals are characteristically needle-shaped and exhibit strong negative birefringence. Under a compensated polarizing microscope, they appear yellow when their long axis is parallel to the slow axis of the red compensator, which is a classic diagnostic finding for gout.
Question 5: The presence of numerous waxy casts in a urine sediment analysis is most strongly associated with which of the following conditions?
- Acute pyelonephritis
- Strenuous exercise
- Chronic end-stage renal disease (Correct answer)
- Urinary tract infection
Correct answer: Chronic end-stage renal disease
Waxy casts represent the final stage of cast degeneration (from cellular to granular to waxy). Their presence indicates extreme urine stasis and tubular damage, and they are most commonly found in patients with severe, long-standing chronic renal failure.
Question 6: A post-vasectomy semen analysis is performed. The initial wet mount examination reveals no spermatozoa. What is the mandatory next step to confirm this finding?
- Report the result as azoospermic.
- Request a new sample collected after a longer abstinence period.
- Centrifuge the specimen and examine the pellet microscopically. (Correct answer)
- Perform a sperm viability stain.
Correct answer: Centrifuge the specimen and examine the pellet microscopically.
To confirm azoospermia in a post-vasectomy sample, the specimen must be centrifuged at a high speed to concentrate any potential sperm, and the resulting pellet must be carefully examined. Reporting azoospermia based only on an initial wet mount is insufficient, as a very low number of non-motile sperm could be missed.
Medical Laboratory Technician Urinalysis and Body Fluids Questions and Answers
A technologist examining a urine sediment under a microscope observes numerous small, round, colorless structures.
Some of these structures appear to be budding.
Which of the following actions would best differentiate yeast from red blood cells?