Collection Protocol

Collect blood in appropriate vacutainer tube. Allow blood to clot at room temperature for 30 to 60 minutes prior to separation. Centrifuge to separate serum from the clot. Transfer (pipette) serum into plain leakproof tube.

Avoid hemolysis and lipemia. Fasting is only necessary to avoid lipemia. If the sample is not lipemic, non-fasting is okay. If the sample is still lipemic after fasting or fasting is medically contraindicated, indicate on the submittal form and submit.

Unspun samples will not be accepted. Do not send whole blood. Do not ship samples in serum separator tubes.

Shipping Requirements

Refrigerate (no longer than overnight) or freeze sample until shipment. Ship on ice via overnight or second day courier.

Prolonged incubation at warm temperatures causes a false increase of free T4 by equilibrium dialysis.

We recommend shipping with an ice pack using the MSU VDL Insulated Mailer with UPS (99220 - Single, 99221 - 3 pack or 99222 - 6 pack).

Additional Information

This profile includes total T4 (TT4), total T3 (TT3), free T4 by equilibrium dialysis (FT4d), T4 autoantibody (T4AA), T3 autoantibody (T3AA), thyroid stimulating hormone (TSH), and thyroglobulin autoantibody (TgAA).

This profile may be performed to diagnose hypothyroidism and/or lymphocytic thyroiditis, or hyperthyroidism (rare) in dogs.

a. If the dog is being treated with steroids, ideally a withdrawal period of 3 – 4 weeks should lapse prior to thyroid testing. If steroid therapy cannot be discontinued, a premium thyroid profile is recommended. Steroids and phenobarbital can decrease thyroid hormone concentrations.
b. Sighthound breeds normally have lower thyroid hormone concentrations compared to other breeds and established (reported) reference intervals.
c. Nonspecific binding can cause false positive thyroglobulin autoantibody (TgAA) results. An extra test is performed to further assess nonspecific binding interference if the TgAA result is above normal.

This profile may also be used in monitoring T4 supplementation. Peak absorption occurs at 3 – 4 hours post supplement administration.
a. Following a change in supplementation dosage, a minimum of 14 days should lapse before monitoring therapeutic levels again.
b. If a dog receives thyroid supplementation and assessment of physiologic thyroid function is desired, withdrawal of thyroid supplementation for at least 6 - 8 weeks may be necessary to fully assess endogenous thyroid production.