Apparent heparin resistance form elevated factor VIII in a patient with postoperative deep venous thrombosis. A case report.

BACKGROUND

During the puerperium, heparin levels, rather than the adjusted partial thromboplastin time test, can be used to identify heparin resistance and guide heparin therapy.

CASE: A patient receiving heparin for deep venous thrombosis had artifactual resistance to heparin, with a short adjusted partial thromboplastin time due to elevation of factor VIII. Heparin assay revealed a heparin level above the therapeutic range.

CONCLUSION

Direct measurement of heparin concentration and factor VIII activity should be performed when heparin resistance is suspected.