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.
Only orderable as part of a profile. For more information see CHF8P / Chromogenic Factor VIII Inhibitor Bethesda Profile, Plasma.
Chromogenic
Bethesda Titer
Plasma Na Cit
Only orderable as part of a profile. For more information see CHF8P / Chromogenic Factor VIII Inhibitor Bethesda Profile, Plasma.
1 mL
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | Reject |
IV heparin contamination | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Plasma Na Cit | Frozen | 14 days |
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.
Factor VIII (FVIII) 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 patients without hemophilia (not previously factor VIII deficient) either spontaneously, during pregnancy, or in association with autoimmune diseases.
Only orderable as part of a profile. For more information see CHF8P / Chromogenic Factor VIII Inhibitor Bethesda Profile, Plasma.
< or =0.5 Bethesda Units
The interpretive report will include assay information, background information, and conclusions based on the test results.
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.
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
In the Bethesda procedure, patient plasma is heat-inactivated (HI) at 56 degrees C for 30 minutes. Next using the HI patient plasma, serial dilutions are prepared and mixed in equal volumes with normal pooled plasma. The mixture is incubated 2 hours at 37 degrees C. At the end of the incubation, chromogenic factor VIII (CH8) activity is measured and compared to a control performed at the same time. The difference between the CH8 activity of the patient's incubation mixture and that of the control is used to calculate the titer. The residual CH8 activity is converted to Bethesda units: 50% residual CH8 is equal to 1 Bethesda unit. Assays using the same basic principle as the Bethesda assay are used to quantitate the inhibitors of the other coagulation factors.(Kasper CK, Aldedort LM, Counts RB, et al: A more uniform measurement of factor VIII inhibitors. Thromb Diath Haemorrh. 1975;34:869-872; Miller C: Laboratory testing for factor VIII and IX inhibitors in haemophilia: A review. Haemophilia. 2018;00:1-12)
Monday through Friday
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
85335
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
CH8B | Chromogenic FVIII Inhibitor Titer,P | 93450-5 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
CH8B | Chromogenic FVIII Inhibitor Titer,P | 93450-5 |