Of all the values on a general blood panel (complete blood count, serum chemistry profile), the platelet count may have the
greatest potential to fool you. I have had several patients referred for severe thrombocytopenia that had normal platelet
counts when I rechecked their complete blood counts. The problem is that blood clots and platelet clumps can dramatically
lower the manual and automated counts. Usually, the laboratory will comment on platelet clumps, but occasionally the clumps
are either not reported or seem to have been missed.
Todd Deppe, DVM, DACVIM
In all the cases mentioned above, the animals had no clinical signs of thrombocytopenia. With these patients in mind, my advice
is if an animal has signs of spontaneous bleeding (petechia, hematuria, hematochezia or melena, prolonged bleeding from venipuncture
sites), believe the first low platelet count and take appropriate action. But if an animal has no clinical signs of thrombocytopenia,
recheck the platelet count before performing an extensive workup or initiating treatment. Recheck the platelet count quickly
(the next day if possible) because the consequences of waiting too long to treat a patient with thrombocytopenia are potentially
severe. If a laboratory is not immediately available, a high-quality blood smear read in-house by an experienced person can
provide inexpensive, rapid confirmation of severe thrombocytopenia.
Todd Deppe, DVM, DACVIM (internal medicine)
Veterinary Medical and Surgical Group
2199 Sperry Ave.
Ventura, CA 93003