CVA Laboratory Techniques & Diagnostic Procedures 5 — Questions and Answers
Question 1: Which of the following is a common zoonotic parasite that can be detected on fecal examination in veterinary patients?
- Toxocara canis (roundworm) (Correct answer)
- Dirofilaria immitis (heartworm)
- Otodectes cynotis (ear mite)
- Demodex canis (mange mite)
Correct answer: Toxocara canis (roundworm)
Toxocara canis eggs shed in dog feces can infect humans, causing visceral or ocular larva migrans, making it an important zoonotic concern.
Question 2: What is the significance of finding white blood cell casts in urine sediment?
- Indicates active pyelonephritis (kidney infection) (Correct answer)
- Suggests lower urinary tract infection only
- Is a normal finding
- Indicates bladder stones
Correct answer: Indicates active pyelonephritis (kidney infection)
WBC casts form in the renal tubules and indicate inflammation or infection within the kidney itself (pyelonephritis), not just the lower urinary tract.
Question 3: When using an in-house chemistry analyzer, a hemolyzed sample may falsely affect which value?
- Potassium (K+), causing a falsely elevated result (Correct answer)
- Sodium, causing a decreased result
- Glucose, causing no interference
- BUN, causing a falsely decreased result
Correct answer: Potassium (K+), causing a falsely elevated result
Red blood cells contain high concentrations of potassium; hemolysis releases intracellular K+ into the sample, falsely elevating the measured potassium level.
Question 4: A Schirmer tear test (STT) result of 6 mm/min in a dog is most consistent with:
- Keratoconjunctivitis sicca (dry eye) (Correct answer)
- Normal tear production
- Excessive tear production
- Corneal ulcer only
Correct answer: Keratoconjunctivitis sicca (dry eye)
Normal STT values in dogs are ≥15 mm/min; a result of 6 mm/min indicates severely reduced tear production consistent with dry eye (KCS).
Question 5: Which technique is used to detect external parasites such as Sarcoptes scabiei mites?
- Superficial skin scraping (Correct answer)
- Deep tissue biopsy
- Urine sediment examination
- Fecal flotation
Correct answer: Superficial skin scraping
Superficial skin scrapings over large areas of skin are used to detect Sarcoptes mites, which live in the superficial layers of the epidermis.
Question 6: What is the role of a control sample when running in-house diagnostic tests?
- To verify that the analyzer and reagents are performing accurately (Correct answer)
- To replace the patient sample if insufficient
- To calibrate the centrifuge speed
- To stain the blood smear
Correct answer: To verify that the analyzer and reagents are performing accurately
Running a known control sample alongside patient samples confirms the machine and reagents are functioning correctly and results are reliable.
Question 7: When performing an ear cytology, finding large numbers of Malassezia organisms most likely indicates:
- Yeast otitis (Correct answer)
- Bacterial otitis caused by Staphylococcus
- Normal ear flora only
- Ear mite infestation
Correct answer: Yeast otitis
Malassezia pachydermatis is a yeast commonly associated with otitis externa; large numbers on cytology indicate yeast-mediated ear infection.
CVA Laboratory Techniques & Diagnostic Procedures 5
Which of the following is a common zoonotic parasite that can be detected on fecal examination in veterinary patients?