Free VTNE Laboratory Procedures Questions and Answers — Questions and Answers
Question 1: A veterinary technician is performing a urinalysis and observes colorless, rectangular, prism-like crystals that resemble "coffin lids." These crystals are most likely:
- Calcium oxalate dihydrate
- Ammonium biurate
- Struvite (Correct answer)
- Cystine
Correct answer: Struvite
Struvite (magnesium ammonium phosphate) crystals are commonly described as resembling 'coffin lids' due to their colorless, three-dimensional, prism-like shape. While they can be found in normal dogs and cats, their formation is favored in neutral to alkaline urine and can be associated with urinary tract infections.
Question 2: A technician prepares a blood smear from a feline EDTA sample that was collected 4 hours prior and kept at room temperature. Upon microscopic examination, the red blood cells appear spiculated with short, evenly spaced projections. This finding is most likely:
- Acanthocytosis, indicating liver disease
- An autoimmune reaction
- Crenation, an artifact from sample aging (Correct answer)
- Heinz body formation due to toxicity
Correct answer: Crenation, an artifact from sample aging
Crenation is a common artifact seen in blood smears, especially from aged samples (left at room temperature for over 2 hours) or due to excess EDTA. It causes red blood cells to develop short, uniform, spiky projections. This is distinct from acanthocytosis, which has irregularly spaced projections and is associated with certain disease states.
Question 3: The Baermann technique is a specialized fecal diagnostic test used to recover which of the following?
- Protozoan cysts like Giardia
- Nematode eggs like Toxocara
- Nematode larvae like Aelurostrongylus (Correct answer)
- Tapeworm segments like Dipylidium
Correct answer: Nematode larvae like Aelurostrongylus
The Baermann technique is specifically designed to recover live nematode larvae from a fresh fecal sample. It relies on the active migration of larvae out of the feces and into surrounding water. It is the preferred method for detecting lungworm larvae (e.g., Aelurostrongylus abstrusus) and other parasites that pass larvae instead of eggs in the stool.
Question 4: When using a standard refractometer in a veterinary clinic, which two measurements are most commonly performed?
- Blood glucose and packed cell volume
- Urine specific gravity and total protein (Correct answer)
- Urine pH and ketone levels
- Blood urea nitrogen and creatinine
Correct answer: Urine specific gravity and total protein
A clinical refractometer is a standard piece of equipment used to measure the refractive index of a fluid. In veterinary practice, its primary uses are to determine the urine specific gravity (USG), which assesses the concentrating ability of the kidneys, and the total protein (TP) or total solids in plasma or serum.
Question 5: A technician needs to perform a Gram stain on a bacterial smear. What is the correct sequence of reagents used in this differential staining procedure?
- Safranin, Iodine, Crystal Violet, Decolorizer
- Crystal Violet, Iodine, Decolorizer, Safranin (Correct answer)
- Iodine, Crystal Violet, Safranin, Decolorizer
- Decolorizer, Safranin, Crystal Violet, Iodine
Correct answer: Crystal Violet, Iodine, Decolorizer, Safranin
The correct order for a Gram stain is: 1) Crystal Violet (primary stain), 2) Gram's Iodine (mordant to fix the stain), 3) a Decolorizer (like alcohol/acetone) to remove the stain from Gram-negative cells, and 4) Safranin (counterstain) to color the decolorized Gram-negative cells red or pink.
Question 6: Which of the following fecal flotation solutions has the highest specific gravity and is therefore most effective at floating heavy parasite eggs, such as Trichuris vulpis?
- Sodium nitrate solution
- Zinc sulfate solution
- Sodium chloride solution
- Sheather's sugar solution (Correct answer)
Correct answer: Sheather's sugar solution
Sheather's sugar solution typically has a specific gravity of around 1.27, which is higher than most standard salt solutions like zinc sulfate (1.18-1.20) or sodium nitrate (1.18-1.20). This higher density is more effective for floating heavier parasite eggs, like those of the whipworm (Trichuris spp.), which might be missed with solutions of lower specific gravity.
Free VTNE Laboratory Procedures Questions and Answers
A veterinary technician is performing a urinalysis and observes colorless, rectangular, prism-like crystals that resemble "coffin lids." These crystals are most likely: