title: Pearls and pitfalls in factor inhibitor assays.
abstract: The proper performance and interpretation of factor inhibitor assays is a critical role for the hemostasis laboratory. Both false-positive and false-negative inhibitor assays may be reported, leading to serious patient mismanagement. Knowledge and recognition of common causes of both false-positive and negative-results can aid in the identification of these potential pitfalls. Safeguards to reporting accurate factor inhibitor assays include initial characterization of the sample, using the Nijmegen modification, properly performing and interpreting an incubated mixing test in conjunction, and performing two dilutions for each dependent dilution in the factor inhibitor assay.
authors.affiliation: Colorado Coagulation, Laboratory Corporation of America® Holdings, Englewood, CO, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Adcock
authors.affiliation: Department of Haematology, Institute of Clinical Pathology and Medical Research, Pathology West, NSW Health Pathology, Westmead Hospital, Sydney, NSW, Australia.
authors.forename: E J
authors.initials: EJ
authors.lastname: Favaloro
mesh_terms: D019774:Blood Coagulation Factor Inhibitors / Q000627:therapeutic use*; D001779:Blood Coagulation Factors / Q000037:antagonists & inhibitors*; D001780:Blood Coagulation Tests / Q000379:methods* / Q000592:standards*; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D011785:Quality Assurance, Health Care / Q000379:methods / Q000592:standards; D015203:Reproducibility of Results
chemical_list: D019774:Blood Coagulation Factor Inhibitors; D001779:Blood Coagulation Factors
keywords: EDTA; Factor inhibitor assay; factor VIII inhibitor; false negative; false positive; lupus anticoagulant