[Pseudothrombocytopenia: case reports and review of the literature].

BACKGROUND: Pseudothrombocytopenia (PTP) is an in vitro phenomenon with falsely low platelet counts determined automatically. Usually the thrombocytopenia is noticed accidentally without a corresponding tendency to bleeding. If this phenomenon is not recognized, misinterpretation may bring the patient into a considerable risk by diagnostical and therapeutical mistakes. By own cases and analysis of the literature, causes, appearance. incidence, as well as diagnostic and clinical problems of PTP shall be explained in detail. CASUISTICS: We report on three patients who showed a significant decrease of platelet counts after surgery DIC (disseminated intravascular coagulation) and heparin-induced thrombocytopenia type II (white clot syndrome) were assumed primarily. In all three cases the reason for the low postoperative platelet counts was found to he due to PTP caused by cold agglutinins. CONCLUSION: From the cases described it can he concluded that PTP may develop during postoperative clinical course. Due to the broad differential diagnostic spectrum in the postoperative situation. PTP is hardly considered. Therefore, there is a greater chance of misinterpretation and therapeutic mistakes. In case of low platelet counts PTP should always be excluded, even when thrombocytopenia seems to be explicable differently.