Test Catalog

Test ID: CH8B    
Chromogenic Factor VIII Inhibitor Bethesda Titer, Plasma

Useful For Suggests clinical disorders or settings where the test may be helpful

Detecting the presence and titer of a specific factor inhibitor directed against coagulation factor VIII


This test is not useful for detecting the presence of inhibitors directed against other clotting factors and will not detect the presence of lupus anticoagulants.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Factor VIII inhibitors are IgG antibodies directed against coagulation FVIII that typically result in development of potentially life-threatening hemorrhage. These antibodies may be alloimmune: developing in patients with congenital FVIII deficiency (hemophilia A) in response to therapeutic infusions of factor VIII concentrate or autoimmune: occurring in nonhemophiliac patients (not previously factor VIII deficient) either spontaneously, during pregnancy, or in association with autoimmune diseases.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Only orderable as part of a profile. For more information see CH8BP / Chromogenic Factor VIII Inhibitor Bethesda Profile, Plasma.


< or =0.5 Bethesda Units

Interpretation Provides information to assist in interpretation of the test results

The interpretive report will include assay information, background information, and conclusions based on the test results.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Contamination with excess heparin and hemodilution due to improper specimen collection through an intravenous access device or collection above a running intravenous fluid line may cause spurious results.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Verbruggen B, van Heerde WL, Laros-van Gorkom BA: Improvements in Factor VIII Inhibitor Detection: From Bethesda to Nijmegen. Semin Thromb Hemost 2009 Nov;35(8):752-759

2. Miller C, Platt S, Rice A, et al: Validation of Nijmegen-Bethesda assay modifications to allow inhibitor measurement during replacement therapy and facilitate inhibitor surveillance. J Thromb Haemost 2012;10:1055-1061

Special Instructions Library of PDFs including pertinent information and forms related to the test