Clinical Pathology and Cytology

Serum specimens

Serum specimens are collected using whole blood in plain Red Top Vacutainer tubes. Serum is necessary for the vast majority of biochemical, hormonal, and drug tests. Serum must be spun down and separated from the clot and submitted separately in a sterile tube, refrigerated (on ice) and shipped overnight, ideally with a 1.0 ml minimum. When ordering multiple tests it is necessary to submit 2 ml of clear serum. It is necessary to separate the serum from the blood clot to minimize hemolysis in serum due to being left on the clot. This is critical for most chemical testing. Blood for glucose testing should be submitted either in fluoride tubes (grey top) or as serum which is separated from the clot within 1 hour of collection prior to shipping.

Whole Blood

Whole Blood is necessary for hematological analysis. The blood is collected in a Purple Top Vacutainer® tube with EDTA anticoagulant (2 ml or 3 ml draw) and shipped refrigerated with ice packs overnight (the tube should not be on ice or hemolysis may occur). Two fresh-drawn, unstained blood smears are required with complete CBC's (air dried and protected from the ice pack). BD Microtainer EDTA tubes are available for use with minimal volume specimens (1 ml). For avian and exotic CBCs it is preferred that both an EDTA and a lithium heprin tubs be submitted, along with two unstained slides.

Lithium Heparinized Blood

Lithium heparinized blood is recommended for most exotic species and for certain biochemical tests (e.g., ionized calcium, ammonia for which plasma is separated and submitted frozen, and for blood gases). Specimens are collected in a Green Top Vacutainer® tube with Lithium Heparin anticoagulant (liquid/powder) and shipped refrigerated (on ice) overnight. BD Microtainer® Lithium Heparin tubes are available for less than 1 ml volumes, and BD Microtainer® Lithium Heparin Serum Separator Tubes are also available for Chemistry specimens. However, a mini Avian panel can be done with 0.25 ml and calcium can be done with 0.5 ml. For non-exotic species, separation of plasma is encouraged. Lithium Heparinized Blood for all chemistry testing must be centrifuged and separated from the blood cells and submitted in a sterile tube.

Citrated Whole Blood

Citrated whole blood is necessary for coagulation tests. It is collected in a Light Blue Top Vacutainer® tube and should be shipped refrigerated (with ice pack) overnight, ideally with > 0.5 ml for a coagulation profile. Interpretation of coagulation tests is most accurate when blood from a control animal of similar age and breed is submitted along with the patient sample(s).

Turnaround times

The listed turnaround times are for samples that arrive prior to 2:30 p.m. in the laboratory where the test will be performed and do not include time associated with shipping. Requests sent to the Athens laboratory for tests that are performed only in the Tifton laboratory (folate/vitamin B12, fructosamine, iron, LH, protein electrophoresis with a liver panel, toxins, and pharmaceutical drugs) require an additional 2 days for shipping. Whenever possible, specimens for tests done only by the Tifton laboratory should be sent directly to Tifton. All specimens shipped to the Tifton laboratory will be analyzed that day and results sent out the same day. Only electrophoresis is batched and performed once a week.

Cytology slides

Cytology slides should be clearly labeled as to site or source of sample. Due to the small space on the slides and the difficulty of reading hand-written labels, a key should be used. For example, slides are labeled by number or letter (1, 2, 3, 4 or A, B, C, D) and the submission form indicates slides 1 & 2 are synovial fluid from the right knee and slides 3 & 4 are from the left knee.

Slides should be properly labeled using a method where the label is not easily dissolved or smeared (frosted slides marked with a pencil work best and do not interfere with staining). Avoid the use of tape wrapped around the slide, which prevents slides from sitting flat on the microscope stage.

Interference

Gross Hemolysis and Lipemia should be AVOIDED. When heavy lipemia is present, use a larger gauge needle to collect blood specimens. This will minimize the hemolysis. Interference by hemolysis, lipemia, and icterus can invalidate certain results, specifically:

  • Lipemia
    Lipemia interferes with evaluation of bile acids, bilirubin, ammonia, ALT, AST, magnesium, and glucose.
  • Hemolysis
    Hemolysis interferes with evaluation of ALT; AST; bilirubin; potassium in horses, cattle, and certain breeds of dogs; LDH; magnesium; phosphorous; protein, urine creatinine/protein ratios, ammonia; creatine kinase; bile acids; GGT; and bicarbonate.
  • Icterus
    Icterus interferes with evaluation of cholesterol, creatinine, triglycerides, lipase, total protein and glucose.