Pseudothrombocytopenia in a patient undergoing splenectomy of an accessory spleen. Case report

Coagulation tests (CBC and prothrombin time) were initially conceived as a mean of screening and following rare congenital coagulopathies; the CBC provides the number of platelets per cubic milliliter. The objective of this report was to present the case of a patient who presented with an extremely low number of platelets when her blood was analyzed in an EDTA-containing tube and its numbers were normal when the blood was analyzed with citrate, alerting for the risk of erroneously administering blood products.

This is the case of a 40-year-old female patient, ASA II. In 2001 she presented with thrombocytopenia and was referred to a hematologist in Manaus, in the state of Amazonas, Brazil and underwent splenectomy that same year with a diagnosis of idiopathic thrombocytopenic purpura. Since her CBCs continued to show thrombocytopenia, an abdominal ultrasound was done and showed a spherical hypoechoic image, with an echotexture similar to the spleen, measuring 2.0 x 1.7 cm, with well-defined contents (accessory spleen), and a splenectomy was indicated. One hour into the surgery, blood samples were drawn for CBC and chemistry: Hb = 11.3 g x dL(-1); Ht = 33.4%; Platelets = 35,000 microL(-1); PT = 15.2 (86.0% Activity) (INR = 1.09). Due to the minimal blood loss in the surgical field, a new test with citrate was requested to determine the platelet count (results: 138,000 platelets).

The anomalous result of an isolated exam without corresponding clinical signs should not guide the treatment. All exams have a defined percentage of errors and the search for those technical errors can avoid the use of the wrong treatment.