CVA Laboratory Sample Handling 5 — Questions and Answers
Question 1: A skin scraping is collected to evaluate for which condition?
- Ringworm (dermatophytosis)
- Bacterial pyoderma
- Mange mites (Demodex or Sarcoptes) (Correct answer)
- Allergic dermatitis
Correct answer: Mange mites (Demodex or Sarcoptes)
Deep skin scrapings are the primary diagnostic method for detecting demodectic and sarcoptic mange mites by scraping until capillary bleeding occurs.
Question 2: What is the purpose of adding formalin to a tissue biopsy sample?
- To keep the tissue alive for culture
- To fix and preserve tissue architecture for histopathology (Correct answer)
- To dissolve lipids before staining
- To prevent hemolysis of blood within the tissue
Correct answer: To fix and preserve tissue architecture for histopathology
10% neutral buffered formalin crosslinks proteins, halting autolysis and preserving tissue morphology for histopathological examination.
Question 3: Which of the following is an appropriate container for submitting a tissue sample for bacterial culture?
- Formalin-filled container
- Sterile culturette swab or sterile container without additives (Correct answer)
- EDTA tube
- Container with saline and preservative
Correct answer: Sterile culturette swab or sterile container without additives
Tissue for culture must be placed in a sterile container without fixatives, as formalin or other preservatives will kill bacteria and prevent growth.
Question 4: When handling a sample labeled as 'biohazardous,' what should the veterinary assistant do?
- Process immediately without PPE since it's already contained
- Wear gloves and handle according to facility biosafety protocols (Correct answer)
- Discard the sample and collect a new one
- Freeze the sample until the veterinarian is available
Correct answer: Wear gloves and handle according to facility biosafety protocols
Biohazardous samples must be handled using appropriate PPE (gloves, eye protection) and facility-specific biosafety protocols to protect staff.
Question 5: How long can a whole blood sample in an EDTA tube typically be stored at room temperature before CBC results become unreliable?
- Up to 24 hours
- Up to 4 hours (Correct answer)
- Up to 72 hours
- Indefinitely if sealed
Correct answer: Up to 4 hours
EDTA whole blood is most reliable when analyzed within 4 hours at room temperature; prolonged storage causes cell swelling and morphological changes.
Question 6: What is the correct ratio of blood to anticoagulant in a blue-top (sodium citrate) tube for coagulation testing?
- 1:1
- 9:1 (Correct answer)
- 4:1
- 1:10
Correct answer: 9:1
Coagulation tubes require a precise 9:1 blood-to-sodium citrate ratio; underfilling dilutes clotting factors and produces inaccurate results.
Question 7: Which parasite is most likely identified on a Baermann technique fecal examination?
- Toxocara cati eggs
- Giardia cysts
- Lungworm larvae (e.g., Aelurostrongylus) (Correct answer)
- Dipylidium caninum proglottids
Correct answer: Lungworm larvae (e.g., Aelurostrongylus)
The Baermann technique uses warm water to stimulate larval migration out of fecal material, making it ideal for detecting lungworm larvae.
CVA Laboratory Sample Handling 5
A skin scraping is collected to evaluate for which condition?