Assessment of interference by heparin cofactor II in the DuPont aca antithrombin-III assay.
Hereditary deficiency of antithrombin-III (AT-III), the major heparin cofactor in human plasma, is a well-established cause of recurrent venous thrombosis. Cross-reactivity of heparin cofactor II (HC II) in assays of AT-III may, in some cases, interfere with the ability to diagnose hereditary deficiency of AT-III. For that reason, we have evaluated the interference by HC II in the new DuPont aca antithrombin assay. Response of the assay to purified AT-III and HC II was compared. Inhibition of the bovine thrombin in the assay was sixfold less per molecule of HC II than of AT-III. This level of selectivity should be adequate to prevent misdiagnosis of patients. Analysis of patient samples showed close correlation (r = 0.91) of values from the automated aca assay with those of a manual assay (Coatest antithrombin, Helena Laboratories).
Hortin
G L
GL
Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110.
Tollefsen
D M
DM
Santoro
S A
SA
D000990:Antithrombin III / Q000032:analysis*; D020152:Antithrombin III Deficiency; D000991:Antithrombins / Q000032:analysis*; D003429:Cross Reactions; D003951:Diagnostic Errors; D006023:Glycoproteins / Q000502:physiology*; D015844:Heparin Cofactor II; D006801:Humans; D011933:Reagent Kits, Diagnostic
D000991:Antithrombins; D006023:Glycoproteins; D011933:Reagent Kits, Diagnostic; D015844:Heparin Cofactor II; D000990:Antithrombin III