VTNE Laboratory Procedures 5 — Questions and Answers
Question 1: A blood smear from a cat shows pale-staining, small RBCs with a high central pallor. What morphology is described?
- Spherocytes
- Hypochromic microcytes (Correct answer)
- Schistocytes
- Acanthocytes
Correct answer: Hypochromic microcytes
Hypochromic microcytes are smaller than normal with increased central pallor, indicating iron deficiency or chronic blood loss impairing hemoglobin synthesis.
Question 2: Which test is the gold standard for confirming hypothyroidism in dogs?
- Total T4 (tT4) by RIA
- Free T4 by equilibrium dialysis (fT4ed) (Correct answer)
- TSH stimulation test
- T3 suppression test
Correct answer: Free T4 by equilibrium dialysis (fT4ed)
Free T4 by equilibrium dialysis is considered the most accurate single test for diagnosing canine hypothyroidism because it is unaffected by binding protein changes and euthyroid sick syndrome.
Question 3: A sample requiring immediate serum separation should ideally be centrifuged within how many minutes of collection?
- 5 minutes
- 30 minutes (Correct answer)
- 2 hours
- 4 hours
Correct answer: 30 minutes
Serum should be separated from the clot within 30 minutes of collection to prevent analyte shifts (e.g., potassium leaking from RBCs, glucose consumption).
Question 4: Which organism causes salmon poisoning disease in dogs in the Pacific Northwest and is transmitted via Nanophyetus salmincola flukes?
- Ehrlichia canis
- Neorickettsia helminthoeca (Correct answer)
- Borrelia burgdorferi
- Anaplasma phagocytophilum
Correct answer: Neorickettsia helminthoeca
Neorickettsia helminthoeca is the rickettsial organism transmitted by the intestinal fluke Nanophyetus salmincola found in raw Pacific salmon, causing potentially fatal salmon poisoning disease.
Question 5: When performing a bone marrow biopsy cytology evaluation, a myeloid:erythroid (M:E) ratio greater than 3:1 suggests:
- Pure red cell aplasia
- Granulocytic hyperplasia or erythroid hypoplasia (Correct answer)
- Erythroid hyperplasia
- Megakaryocyte hypoplasia
Correct answer: Granulocytic hyperplasia or erythroid hypoplasia
A high M:E ratio (>3:1) indicates either increased granulocytic production (e.g., infection, inflammation) or decreased erythroid production.
Question 6: Which finding on a urinalysis sediment is pathognomonic for ethylene glycol toxicity in cats?
- Struvite crystals
- Calcium oxalate monohydrate crystals (hippurate-shaped) (Correct answer)
- Bilirubin crystals
- Uric acid crystals
Correct answer: Calcium oxalate monohydrate crystals (hippurate-shaped)
Calcium oxalate monohydrate crystals (envelope- or hippurate-shaped in cats) in large numbers in fresh urine are characteristic of ethylene glycol (antifreeze) poisoning.
Question 7: A quality control chart shows three consecutive values on the same side of the mean. This pattern is called a:
- Random error
- Westgard 3s violation
- Trend or shift warning (Correct answer)
- Coefficient of variation breach
Correct answer: Trend or shift warning
Three or more consecutive QC values on the same side of the mean suggest a systematic trend or shift in the assay, warranting investigation before patient results are reported.
VTNE Laboratory Procedures 5
A blood smear from a cat shows pale-staining, small RBCs with a high central pallor.
What morphology is described?