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.
I agree that cold agglutinin
I agree that cold agglutinins commonly don’t’t influence plasma coagulation tests, however, in some rare cases, IgM autoantibodies can induce in vitro precipitation of coagulation factor , especially factor V. Here is the case report: Williams EC. Cold-induced in vitro precipitation of factor V in a patient with monoclonal IgM cryoglobulinemia. Thromb Haemost. 1987;57:236–7.
Recently we also saw a case similar to the above-mentioned report, a patient with Raynaud’s phenomenon (final diagnosis was lymphoplasmacytic lymphoma) had a significantly prolonged PT and APTT, in further coagulation factors investigation a single factor V deficiency (5%) was found. As this patient had no apparent bleeding symptoms, a repeated factor V assay was performed with sample transporting and centrifuging at 37℃, result of factor V level was increased from 5% to 37%, and both of PT and APTT were significantly shortened. Surely, it’s very rare.