Laboratory Techniques & Diagnostic Procedures Flashcards

What is the correct needle angle for venipuncture of the cephalic vein in a dog?

Answer: 15–30 degrees

A 15–30 degree angle allows the needle to enter the vein smoothly without passing through the opposite wall.

Which finding on a urinalysis sediment examination is most indicative of a bacterial urinary tract infection?

Answer: Bacteria and white blood cells (pyuria)

The combination of bacteria and white blood cells (pyuria) in urine sediment strongly suggests active bacterial infection.

A packed cell volume (PCV) of 18% in a cat most likely indicates:

Answer: Anemia

Normal PCV in cats is 24–45%; a PCV of 18% is below the reference range, indicating anemia.

When reading a fecal flotation slide under the microscope, which objective lens is typically used first?

Answer: 4x or 10x (low power)

Low-power objectives (4x or 10x) are used first to scan the entire coverslip area before switching to higher magnification for identification.

What is the purpose of adding EDTA anticoagulant to a blood collection tube?

Answer: It chelates calcium to prevent clotting

EDTA chelates (binds) calcium ions, which are required for the clotting cascade, thus preventing coagulation.

Which diagnostic test is most appropriate for identifying ringworm (dermatophytosis) in a cat?

Answer: Fungal culture (DTM agar) and Wood's lamp examination

Dermatophyte Test Medium (DTM) fungal culture is the gold standard for diagnosing ringworm, and a Wood's lamp can screen for Microsporum canis fluorescence.

In a blood smear, platelets are best evaluated using which objective?

Answer: 100x oil immersion

Platelets are very small and must be viewed under 100x oil immersion to accurately assess their morphology and estimate numbers.