VTNE Laboratory Procedures 2 — Questions and Answers
Question 1: Which anticoagulant is found in a purple-top (lavender) tube and is used for complete blood counts?
- Sodium citrate
- Heparin
- EDTA (Correct answer)
- Sodium fluoride
Correct answer: EDTA
EDTA (ethylenediaminetetraacetic acid) chelates calcium and is the anticoagulant of choice for CBCs because it preserves cell morphology.
Question 2: A urine specific gravity of 1.008–1.012 in a dog is classified as:
- Hypersthenuria
- Isosthenuria (Correct answer)
- Hyposthenuria
- Normosthenuria
Correct answer: Isosthenuria
Isosthenuria refers to urine specific gravity in the range of 1.008–1.012, which is similar to glomerular filtrate and indicates inadequate concentrating or diluting ability.
Question 3: When performing a blood smear, the feathered edge is used to evaluate:
- Red blood cell indices
- Platelet clumps and large cells (Correct answer)
- Packed cell volume
- Reticulocyte count
Correct answer: Platelet clumps and large cells
The feathered edge of a blood smear is where platelets tend to clump and large cells such as monocytes accumulate, making it an important area to scan.
Question 4: Which stain is used to identify reticulocytes in a peripheral blood smear?
- Wright-Giemsa stain
- New methylene blue stain (Correct answer)
- Gram stain
- Diff-Quik stain
Correct answer: New methylene blue stain
New methylene blue is a supravital stain that precipitates residual RNA in reticulocytes, making them identifiable as cells with blue granular network.
Question 5: A sample for blood glucose measurement is collected in a gray-top tube. What additive does it contain?
- EDTA and thrombin
- Sodium citrate
- Sodium fluoride and potassium oxalate (Correct answer)
- Lithium heparin
Correct answer: Sodium fluoride and potassium oxalate
Gray-top tubes contain sodium fluoride (a glycolytic inhibitor) and potassium oxalate (an anticoagulant), preserving glucose levels for accurate measurement.
Question 6: On a urinalysis, which finding is considered NORMAL in small animals?
- 3+ glucosuria
- Occasional hyaline casts (0–2/lpf) (Correct answer)
- 4+ proteinuria
- Numerous WBCs (>5/hpf)
Correct answer: Occasional hyaline casts (0–2/lpf)
Occasional hyaline casts (0–2 per low-power field) can be a normal finding, as they form from Tamm-Horsfall protein secreted by tubular cells.
Question 7: Which QC procedure should be performed each time a new lot of reagent strips is opened for urinalysis?
- Run a serum control sample
- Perform a specific gravity comparison with a refractometer
- Run positive and negative control solutions (Correct answer)
- Recalibrate the spectrophotometer
Correct answer: Run positive and negative control solutions
Running both positive and negative controls verifies that the new reagent strip lot is performing correctly before patient samples are tested.
VTNE Laboratory Procedures 2
Which anticoagulant is found in a purple-top (lavender) tube and is used for complete blood counts?