This tube stabilizes the specimen’s glucose component during transport. It must be at least 50% filled or the high concentration of sodium fluoride will interfere with glucose testing methods. The preferred method to stabilize a specimen for glucose and other chemistry assays is to collect a serum separator tube (SST), and centrifuge it after it clots to separate the serum from the blood cells. Alternately, draw a plain red top tube (RTT), centrifuge it, and transfer the serum to another RTT.

Drugs such as digoxin and phenobarbital are most stable in blood samples drawn into a RTT, as the silicone gel of SST will absorb many drugs. Vitamin B12 and folate levels also may be affected by the SST gel, although elemental therapies such as bromides do not appear to be altered.

Coagulation Testing Blood samples for coagulation testing must be drawn into a blue top tube (BTT). The BTT should be filled to at least 75%, but preferably 90% capacity, or results will be affected by the excess citrate anticoagulant. Generally, centrifugation and separation of plasma from the cells is preferred if trans- port to the lab takes more than 12 hours. Use a plastic pipette or small syringe to transfer the plasma to a clean plastic tube. Cap the plastic tube and keep cold or freeze at -20ºC or lower. Freezing the plasma is not necessary unless testing will be delayed for more than 24 hours, but it should always stay cold. Repeated freezing and thawing of plasma denatures coagulation proteins. The ANTECH drivers have coolers to transport local samples. Samples being mailed in should be shipped overnight with frozen cold packs.

Plasma von Willebrand factor can be measured in samples collected in either BTT or lavender top tube (LTT), following the guidelines above.

Specimens should be collected into Microtainer devices. Ideally, in avians, the EDTA Microtainer is used for CBC and heparinized Microtainer for blood chemistries. In reptiles, only heparinized Microtainers should be submitted, as EDTA causes hemolysis and clotting. Fresh blood smears should always be submitted, so that cellular morphology is preserved. Coverslip smears are discouraged. If only a very small quantity of blood is obtained, the most versatile specimen is the heparinized Microtainer. As a general guideline for avians and reptiles, 10% of the body weight is blood, and 10% of that can be safely phlebotomized (roughly 1% of the body weight or 0.1 ml/10 gm).

Collection of urine should be performed in such a way to permit both urinalysis (UA) and culture. Although normal urine is sterile, it is a wonderful medium for growth of both pathogenic bacteria and normal flora. A single contaminating bacterium can overgrow a urine specimen in 2 to 4 hours. Stabilizers are available to preserve a urine specimen for culture, however they render the specimen unsuitable for routine UA. Therefore, urine specimens are best split, with a portion submitted in a RTT for UA and another submitted in a urine culture stabilizing tube. All urine specimens, whether for UA or culture, should be refrigerated and transported with a cold pack to prevent bacterial overgrowth and stabilize cellular components.

Specimens for blood culture require collection into a specialized vacuum tube containing growth medium. The area should be shaved, scrubbed clean with soap and water, and disinfected twice with an iodine preparation, beginning at the venipuncture site and working outward. Allow the site to dry. The rubber stopper of the growth medium tube should be disinfected with alcohol. It will draw up to 4 ml of blood, and even though a small sample c an provide diagnostic information, a larger volume will more likely permit recovery of an infectious organism. Draw 2 tubes taken 1 to 2 hours apart with the animal off all antibiotics for at least 2 days. Leave the culture tubes at room temperature during transport.

Aprotonin (protease inhibitor) is added to LTT to stabilize ACTH so that the sample does not need to be frozen. [These tubes are available from ANTECH.] The treated plasma is separated by centrifugation, transferred to a plastic tube, capped and refrigerated. Transport the sample to the lab with cold packs.