The adequate performance and correct interpretation of assays for coagulation factor inhibitors play a critical role for the hemostasis laboratory. Both, false positive and false negative inhibitor assays may be reported, leading to erroneous patient’s management. Therefore, we decided to present a case with a spurious image of an exceptionally rare acquired combined haemophilia A, B and C, with severe factor ( F) VIII, IX and XI deficiency, associated with high titre anti - F VIII, IX and XI inhibitors in a 4 years old girl with Henoch-Schönlein type vasculitis. Finally, performing, beside coagulometric methods also antigenic ELISA assays, we had to invalidate the diagnosis. The performance of antiphospholipd antibodies clarified the diagnosis , finally concluding as definite diagnosis Transient Lupus Anticoagulant Syndrome, with decisive impact on therapy and follow-up.