Comparison of 2 Methods of Clot Solubility Testing in Detection of Factor XIII Deficiency.

BACKGROUND: Deficiency of factor XIII (FXIII) is a rare bleeding disorder (RBD) affecting approximately 1 person per 2 million worldwide. Its life-threatening diatheses-umbilical cord bleeding, intracranial hemorrhage and central nervous system bleeding-present a significant challenge in both diagnosis and treatment. Confirming FXIII deficiency (FXIIID) is difficult and has been most commonly performed with the clot solubility test. Iran has limited resources and a rate of FXIIID 12-fold higher than the rest of the world, suggesting that in this country optimization of the clot solubility test is crucial. For this reason, we compared clot solubility test methods traditionally used in Iran.

METHODS: In this study, we assessed patients suspected to have FXIIID with routine coagulation tests and 2 different methods of clot solubility testing including 5M urea and monochloroacetic acid (MCA) as solubilizing agents, and thrombin and calcium chloride as clotting agents. Finally, we analyzed the data obtained with SPSS software.

RESULTS: During the study period, we were referred 83 patients with normal routine coagulation tests, of which 29 patients had abnormal clot solubility test results with 5M urea, and 21 had abnormal results with MCA (P = .03); 19 cases had abnormal results with both methods; 2 patients had abnormal results with MCA but normal results with urea. Ten patients had positive results with urea but normal results with MCA.

CONCLUSION: The clot solubility test with 5M urea as solubilizing method and thrombin as clotting agent is more sensitive in the detection of FXIIID, but simultaneous use of the 2 methods can prevent misdiagnosis of a considerable number of patients with FXIIID.