VTNE Laboratory Procedures 4 — Questions and Answers
Question 1: What is the most likely interpretation if a blood sample shows marked lipemia on a serum chemistry panel?
- Hemolysis artifact only
- Post-prandial state or hyperlipidemia disorder (Correct answer)
- Severe anemia
- In vitro glucose consumption
Correct answer: Post-prandial state or hyperlipidemia disorder
Lipemia (milky appearance) in serum is most commonly caused by post-prandial triglyceride elevation or a primary hyperlipidemia disorder, and can interfere with multiple chemistry analytes.
Question 2: When using an automated cell counter, which parameter is most commonly falsely elevated by platelet clumping?
- Red blood cell count
- White blood cell count (Correct answer)
- Platelet count
- Mean corpuscular volume (MCV)
Correct answer: White blood cell count
Platelet clumps are counted as white blood cells by impedance-based analyzers because their combined size falls within the WBC detection threshold, falsely elevating the WBC count.
Question 3: A cat has a PCV of 18% and the plasma appears icteric. Which additional test is most appropriate next?
- Serum lipase
- Direct and total bilirubin (Correct answer)
- Serum creatinine
- Urine culture
Correct answer: Direct and total bilirubin
Icteric plasma with anemia warrants measurement of bilirubin fractions to differentiate prehepatic (hemolytic), hepatic, and posthepatic causes of icterus.
Question 4: Which organism is identified by a positive Voges-Proskauer (VP) test in bacteriology?
- Escherichia coli
- Klebsiella pneumoniae (Correct answer)
- Pasteurella multocida
- Pseudomonas aeruginosa
Correct answer: Klebsiella pneumoniae
Klebsiella pneumoniae produces acetoin (detected by the VP test), whereas E. coli is VP-negative — a key distinction between these Enterobacteriaceae.
Question 5: The PIVKA test (Proteins Induced by Vitamin K Absence or Antagonism) is used to diagnose:
- Disseminated intravascular coagulation (DIC)
- Rodenticide anticoagulant toxicosis (Correct answer)
- Von Willebrand disease
- Immune-mediated thrombocytopenia
Correct answer: Rodenticide anticoagulant toxicosis
PIVKA (also called Thrombotest or Normotest) detects inactive clotting factors caused by vitamin K deficiency or antagonism, as seen with anticoagulant rodenticide ingestion.
Question 6: On cytology, which cell type is predominant in a well-differentiated mast cell tumor aspirate?
- Spindle cells with intranuclear inclusions
- Round cells with purple granules and a central nucleus (Correct answer)
- Epithelial cells in clusters
- Lymphoblasts with scant cytoplasm
Correct answer: Round cells with purple granules and a central nucleus
Mast cells are round cells characterized by abundant purple (metachromatic) cytoplasmic granules surrounding a central to eccentric nucleus on Romanowsky-stained preparations.
Question 7: Which fecal egg flotation solution has the highest specific gravity and is best for recovering heavy parasite eggs such as Taenia spp.?
- Sodium nitrate (SG 1.20)
- Zinc sulfate (SG 1.18)
- Sugar (Sheather's) solution (SG 1.27) (Correct answer)
- Sodium chloride (SG 1.20)
Correct answer: Sugar (Sheather's) solution (SG 1.27)
Sheather's sugar solution has a specific gravity of approximately 1.27, making it capable of floating heavier eggs including tapeworm eggs that may sink in lower SG solutions.
VTNE Laboratory Procedures 4
What is the most likely interpretation if a blood sample shows marked lipemia on a serum chemistry panel?