December 2008
Feature Story

A 28-year-old woman delivered a term infant by vaginal delivery. There was little bleeding during delivery, and the patient was discharged 1 day postpartum. At day 3 postpartum, the patient developed extensive vaginal bleeding, with a hemoglobin of 9 g/dL, requiring hospitalization and transfusion. The patient related a similar delayed bleeding episode after a tonsillectomy at the age of 7 years, but no coagulation evaluation had been performed at that time.

At the time of admission, the PT was 10.0 seconds (reference range, 9.9�13.0) and the aPTT was 28.9 seconds (reference range, 24.6�32.8) with a normal platelet count. After the initial coagulation study results were obtained, repeat testing of PT and aPTT was performed, with similar normal results. Further testing showed a normal Clauss fibrinogen of 325 mg/dL (reference range, 200�400), a normal D-dimer of 280 ng/mL fibrinogen equivalent units (FEU) (normal level, <500), and a normal platelet function screen with the PFA-100 (collagen/epinephrine closure time, 175 seconds [normal level, <198] and collagen/adenosine diphosphate [ADP] closure time, 115 seconds [normal level, <118]). These results do not suggest a coagulation protein disorder in the common, intrinsic, or extrinsic pathways, nor do they suggest a fibrinolytic or platelet disorder. For this reason, a qualitative factor XIII urea solubility assay was performed, which was abnormal. Sub�sequent quantitative factor XIII assay sent to a reference laboratory showed a decreased factor XIII activity of 3%, and a diagnosis of factor XIII deficiency was rendered. This case illustrates that significant clinical bleeding can be seen with normal PT and aPTT results in the setting of a factor XIII deficiency because factor XIII is responsible for cross-linking fibrin.