The Veterinary Practice Laboratory – Key Terminology (VET 152)

Vocabulary-style terms and definitions covering safety, equipment, and quality control topics from the lecture notes.

What is the role of a veterinary technician in the laboratory?

To perform diagnostic tests, interpret and record results accurately, maintain equipment, ensure quality control, manage supplies, and follow OSHA and safety protocols. Technicians interpret but do not diagnose.

Why must veterinary technicians understand laboratory results even though they cannot diagnose?

Understanding results ensures accurate test performance, recognition of abnormal values, and the ability to communicate findings to veterinarians, supporting diagnosis and treatment.

What are the key components of a laboratory safety program?

Written policies, hazard identification, PPE use, access to SDS, proper labeling, safe specimen handling, equipment maintenance, biohazard waste disposal, spill cleanup, and posted safety signs.

What is zoonosis, and why is it important in the veterinary lab?

Zoonosis is disease transmission from animals to humans. Labs must prevent exposure through PPE, disinfection, proper disposal, and minimizing contact with infectious agents.

What are Category A and Category B specimens in shipping? Give an example of each.

Category A: high-risk pathogens likely to cause severe, life-threatening, or fatal disease (e.g., Bacillus anthracis). Category B: lower-risk, not life-threatening in healthy individuals (most patient samples).

What are the requirements for properly shipping biological specimens?

Leak-proof primary container, secondary watertight container with absorbent material, sturdy outer packaging, and correct infectious substance label.

What laboratory features are essential for efficiency and safety?

Dedicated space away from hospital traffic, easy-to-clean counters and floors, sinks, adequate storage, refrigerators/freezers, electrical outlets, internet access, and clutter-free work surfaces.

What are the main functions of a refractometer in the veterinary laboratory?

To measure refractive index, which determines urine specific gravity, protein concentration in plasma/serum, and other fluid analyses (e.g., synovial fluid).

Why is centrifugation critical in veterinary diagnostics?

It separates solid components (sediment) from liquid (supernatant), allowing clearer analysis of blood, urine, and other fluids. Proper speed and time are essential to avoid cell rupture or incomplete separation.

what happens if samples are spun incorrectly?

The centrifuge is essential for separating cells and particulates from fluid samples, producing sediment and supernatant for analysis. If spun too long or too fast, cells may rupture and morphology changes occur. If spun too slow or not long enough, complete separation is not achieved, leading to inaccurate results.

What are the types of centrifuges used in veterinary labs?

Microhematocrit centrifuge (packed cell volume), Clinical centrifuge (larger blood/urine tubes), Angled centrifuge (fixed tube angle, higher speeds), Swinging arm centrifuge (cups swing horizontally during spin).

Why must centrifuge tubes be counterbalanced?

To prevent vibration, spills, uneven separation, and damage to the centrifuge. Unbalanced spinning can distort results and break tubes.

What is the correct process for using the oil-immersion (100x) objective lens on a microscope?

Focus with low (10x) and high power (40x), rotate halfway, apply immersion oil, move to 100x, use fine adjustment only, then clean lens and return microscope to low power when finished.

Define accuracy, precision, and reliability in laboratory testing.

Accuracy = closeness to true value. Precision = reproducibility of results (low random error). Reliability = consistent ability to be both accurate and precise.

What are examples of pre-analytic errors in the veterinary lab?

Patient-related (breed, age, sex), collection issues (non-fasted sample, hemolysis, clotting), mislabeling, or poor handling/storage of specimens.

What are analytic errors, and how can they be prevented?

Errors during testing such as faulty equipment, expired reagents, incorrect standards, or poor calibration. Prevented by regular maintenance, controls, and SOP adherence.

What is the purpose of quality control logs in the lab?

To document instrument calibration, reagent stability, test performance, and technician consistency—ensuring valid and reproducible results.

Define Mean Corpuscular Volume (MCV) and its formula.

The average size of RBCs. Formula: (PCV \times 10) \div RBC count = femtoliters (fL).

Define Mean Corpuscular Hemoglobin (MCH) and its formula.

The average weight of hemoglobin per RBC. Formula: (Hb \times 10) \div RBC count = picograms (pg).

Define Mean Corpuscular Hemoglobin Concentration (MCHC) and its formula.

The concentration of hemoglobin in RBCs. Formula: (Hb \times 100) \div PCV = g/dL. Normal: "30–36 g/dL".

How do RBC indices help classify anemia?

MCV indicates microcytic, normocytic, or macrocytic anemia. MCH/MCHC indicate hypochromic or normochromic anemia. Together, they help determine anemia type (iron deficiency, regenerative, etc.).

What would low MCH and MCHC values indicate on a blood smear?

Hypochromic RBCs—cells appear paler due to reduced hemoglobin content.

Why must RBC indices be compared to blood smear morphology?

Automated calculations may miss abnormalities (anisocytosis, poikilocytosis, polychromasia). Microscopic confirmation ensures accurate interpretation.