RESUMO
Although specific criteria for diagnosing the antiphospholipid syndrome (APS) exist (the Sapporo Criteria), most physicians are not aware these include repeat testing and documentation of either a lupus anticoagulant or medium to high levels of anti-cardiolipin antibody. Incorrect diagnosis of APS may result in unnecessary long-term anticoagulation. The purpose of this study was to determine the clinical and serological characteristics of patients being treated for APS and concordance with published criteria. This cross-sectional study identified APS patients who were being treated with warfarin at one of three university-based anticoagulation clinics. Levels of anticardiolipin antibody were classified as low-positive if abnormal but < 40 GPL/MPL units and medium/high-positive if > or = 40 units. Strength of meeting Sapporo criteria was graded as definite, possible, and not meeting criteria. Of 103 cases, 97 had clinical and laboratory data available. Only 10 cases (10%, 95% Confidence Interval 5 - 19) met criteria for definite APS, 16 (16%, 10 - 26) had a possible diagnosis, and 71 (73%, 63 - 81) did not meet criteria. Of 70 cases that had abnormal anticardiolipin antibody results, only 32 (46%, 34 - 58) had medium/high-positive levels. Repeat laboratory testing was performed in only 49 cases (51%, 40 - 61). We conclude that few patients treated forAPS met Sapporo criteria. Abnormal levels of anticardiolipin antibody were frequently in the low-positive range, and repeat testing was often absent. A quality improvement program that includes review of cases referred for chronic anticoagulation care is recommended to ensure appropriate testing and treatment of patients with suspected APS.