A laboratory test is only as good as the sample submitted. That sample should be collected, stored and shipped properly, with appropriate paperwork, for the most reliable and accurate results. Among possible samples that can be submitted to a laboratory for testing are serum, whole blood, feces, urine, swabs, washes, tissue samples, biopsies, feed, hay, water and entire animals. The following guidelines will help get the most information from diagnostic submissions.
Serum is often required when a titer, or antibody determination, is desired. If serum is needed, allow the blood to clot, then pour the serum into a different clean tube. Allowing the serum to sit on the clot too long can cause the red blood cells to rupture, or hemolyze. Hemolysis will interfere with many laboratory tests. Gel tubes, or serum separator tubes, are meant to aid the separation of serum from red cells following centrifugation and are not optimal for shipping.
Tests such as complete cell counts, virus isolation and polymerase chain reaction assays often require submission of plasma or whole blood. For these tests, blood needs to be unclotted, therefore, use tubes containing an appropriate anticoagulant and have been gently inverted five to six times after collection.
Samples should be submitted using proper biosecurity guidelines in capped, clean, leak-proof, spill-proof, labeled containers. And, while a palpation sleeve would seem to be the perfect, convenient submission container (especially for fecal specimens), it is not an acceptable vehicle for samples.
Storage on the dashboard or console of a vehicle is not optimal. Most samples need to be kept cool. Tissues in formalin need not be cooled, but must be in leak-proof containers. Serious monetary fines from shipping companies or laboratories may be imposed as formalin is a hazardous substance. Shipping on cold packs for next day delivery is recommended for most biological samples. Samples should be sent in sturdy, insulated packaging that will not allow the specimen or container to be crushed in transit. Padded envelopes are not sufficient for shipping blood tubes.
The paperwork is critical, beginning with the labeling of the specimen. Label the specimen minimally with the name/ID # of the animal, contents and date. The submission form needs to be filled out as completely as possible. The collection date is important and imperative for regulatory tests. As a general rule, the more history, the better. Be sure to indicate treatments with antibiotics, recent vaccinations, etc., because these can impact test results and interpretation.
If an entire animal is submitted for necropsy, be mindful that decomposition begins quickly in warmer weather. If the animal is submitted for a neurologic examination or is a rabies suspect, do not damage the brain. Gunshot or blunt force trauma to the head is contraindicated for a testable specimen.
Finally, to save valuable time and money, if there are any questions call the laboratory ahead of time.
Contact Dr. Deborah Maples of the University of Kentucky’s Veterinary Diagnostic Laboratory at 859-257-8283, or email her at [email protected].
Information provided by the University of Kentucky Gluck Equine Research Center’s Lloyd’s Equine Disease Quarterly.