Abstract
Objective
Lupus anticoagulant (LAC) and antiphospholipid antibodies (aPL), both further summarized as aPL, are frequently assessed in routine daily clinical practice in diagnostic work-up for suspected autoimmune diseases or to test for underlying risk factors in patients with thrombosis or obstetric complications. The aim of this study is to determine the prevalence of aPL positivity in patients with an indication for aPL testing in routine clinical practice.
Methods
In this retrospective single center study indication for aPL testing, aPL test results and clinical data were collected for patients tested between June 2015 and April 2018.
Results
During the study period, 16,847 single aPL tests were performed in 2,139 patients. In 212 patients ≥1 positive aPL test was found, confirmed in 43.9% with a second positive test. Indications for aPL testing were diagnostic work-up/follow-up of autoimmune diseases (33.6%), thrombosis (21.4%) and obstetrical complications (28%). Seventy-four patients (3.5% of all patients) fulfilled the criteria of the antiphospholipid syndrome (APS), of whom 51% were newly diagnosed. Second positive aPL titers and titers of APS patients were significantly higher compared with positive aPL titers at first measurement (p < 0.05). Patients with indication arterial thrombosis and diagnostic work-up/follow-up of autoimmune diseases had significantly higher levels of aCL IgG and anti-β2GPI IgG compared with patients with other indications.
Conclusion
Prevalence of ≥ 1 positive aPL test was 9.9% and APS was diagnosed in 3.5% of the patients. Patients with arterial thrombosis had significantly higher anti-β2GPI IgG and aCL IgG, which should be confirmed in future studies.