From Lissette, UCLA: We requested our hematology specimens to be sent with a warm pack for CBC/DIFF. Is it recommended to keep the sodium citrate tubes for coagulation testing on
warm packs as well for patients with cold agglutinin? Is there a recommended method to workup these specimens for coagulation testing?
Hello, and thank you for your question. I (Geo) know of no interaction between cold-reacting IgM autoantibodies and the coagulation system, nor do I find any references on the subject, however in our April 26, 2018 entry discussing pseudothrombocytopenia, Dr. Guiseppi Lippi is quoted by Dr. Emmanuel Favaloro as finding cold antibodies associated with platelet clumping. I would suggest that in general, prolonged warming of sodium citrate tubes should be avoided because of the heat-related lability of factors V and VIII. I hope this is helpful.