[Biological diagnosis of postoperative thrombopenia]

The recognition of the postoperative thrombopenia is important because thrombopenia give an hemorrhage risk and modify the tolerance to preventive anticoagulant treatments. Some thrombopenias can be iatrogenic: thrombopenias by transfusion of a large volume of preserved blood, or by hemodilution, but require a substitution, therapy are easily diagnosed. Post-transfusional thrombopenias require an antibody analysis (especially for antiPLA1). The search for drugs interactions is often complex; heparin induced thrombopenia constitutes a severe but fortunately a rare complication of the heparin therapy. Other thrombopenias are related to operative complications this is the case of consumption-coagulopathies due to infections, the release of thromboplastin from tissues, hepatic cirrhosis, pancreatitis, etc. The evaluation of hemostasis verifies clinical hypotheses and guides the treatment. Thrombopenias can be due to various disorders revealed or occurring during an operation. Although the concurrences are rare, they do not always preclude the possibility of finding a collagen disease (connectivitis), a thrombocytogenetic thrombotic purpura, and especially an idiopathic thrombopenic purpura. In any case, diagnosis is easier if the preoperative platelet levels are known. Thus, platelet counts should be included in pre and postoperative evaluations.