Specimen Collection Information

Serum should be collected from clotted samples in a red top or tiger top tube with a clotting activator or a Serum Separator Tube (SST) with a gold top. Please refer to individual tests in the testing catalog to determine the best tube for each test. Serum and plasma need to be separated from red blood cells and placed in a secondary vial as soon as possible (within 60 minutes).  Allow serum samples to clot completely before centrifuging. Even when using serum separator tubes, serum should be decanted into another tube before shipping as red cells can diffuse through the gel after a few hours.

Tests performed on plasma require blood collected in tubes containing an anti-coagulant – usually a green top (heparin) or purple top (EDTA). Check the specific test listing for container requirements.

Plasma and serum cannot be used alternately in all situations; please refer to the test for specific instructions to ensure submittal of the correct sample.

For detailed instructions, please see the specific test information located in the test search.

Whole blood samples need to be protected from temperature extremes as heating or freezing destroys cellular elements.  Please ship samples with sufficient cold packs in an insulated container.

Samples should be collected by cystocentesis, if possible, and sent with cold packs to decrease cell deterioration and bacterial overgrowth.

Slides should be protected from moisture, formalin fumes and breakage.  Do not refrigerate air-dried slides as condensation can form and lyse cellular elements.

For body fluid cytology, an aliquot of the fluid should be placed in an EDTA tube if available. Body fluids should be sent with cold packs.  If sending syringes, please remove needles and cap the syringe tip.

Swabs should be labeled with the identity of the source material and protected from formalin fumes.  See individual tests for specific requirements (dry swab, media etc.).

Fecal samples should be submitted in a sealed plastic bag with minimal exposure to air and kept cool to preventing hatching of eggs.

The nutrient composition of animal feed (i.e. hay, grain, forage, or rations) is often highly variable, therefore, collecting a representative sample for nutrient and/or toxin analysis is the most important step in the analysis process. The results of a feed analysis are only as good as the quality of the sample submitted to the laboratory. In order to obtain the most reliable results, the sample collected must be representative of its totality. For this reason the following sample collection recommendations are provided:

Bulk Feeds: Collect and combine into a single (i.e. composite) sample aliquots from different areas of the bin, bunk, bags, or etc. Total quantity of the composited sample should be approximately one (1) pound.

Baled Hay: Collect and combine into a composite core sample from 10% of the total number of bales.

Forages: Collect and combine into a composite sample 10 to 15 plants or small samples (i.e. handful) or forage from throughout the field or pasture.

Samples submitted for histopathology should be representative of the lesion (if noted) and the adjacent normal tissue.  The ratio of formalin to sample should be at least 10 parts formalin to one part tissue.  Samples should be in a wide mouth, break-resistant (not glass), leak proof container.  For necropsies, samples should be collected both in formalin and fresh.

In order to prevent additional decomposition during transit, specimens intended for histopathological examinations should always be submitted in formalin. We have formalin jars in triple containers available to order on the TVMDL Supplies form.

Tissue samples should be submitted on cold packs (not cubed ice) in an insulated container with the tissues being triple bagged.  Sample size and other factors may vary by test so please check the specific test for shipping instructions.

Hair samples should be pulled, ensuring the follicle is still intact, until the total amount of hair collected is approximately 1 cm in diameter (i.e. as wide as a pencil). Protect samples by placing them in a piece of foil or paper towel with the root end clearly labeled. Then samples should be placed inside a plastic bag. Do not store samples in refrigerator, freezer, or direct sunlight.

A carcass with little or no decomposition is obviously one of the best diagnostic specimens. Carcasses intended for necropsy should be kept refrigerated, but not frozen, as freeze/thaw artifacts obscure gross and microscopic lesions. Do not drop entire small carcasses such as birds or rodents into formalin, since internal organs do not get fixed properly by this procedure. Regardless of whether the carcass is fresh or fixed, a necropsy fee will be charged if TVMDL has to perform a necropsy on the submitted specimen.