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HelpMayo Test ID GBETH General Factor Bethesda Units, Plasma
Ordering Guidance
If type of inhibitor is unknown, see APROL / Prolonged Clot Time Profile, Plasma.
Specimen Required
Only orderable as a reflex. For more information see:
-ALBLD / Bleeding Diathesis Profile, Limited, Plasma
-APROL / Prolonged Clot Time Profile, Plasma
-2INHE / Factor II Inhibitor Evaluation, Plasma
-7INHE / Factor VII Inhibitor Evaluation, Plasma
-10INE / Factor X Inhibitor Evaluation, Plasma
-11INE / Factor XI Inhibitor Evaluation, Plasma
Useful For
Detecting and quantifying the presence and titer of a specific factor inhibitor directed against a specific coagulation factor
Method Name
Only orderable as a reflex. For more information see:
-ALBLD / Bleeding Diathesis Profile, Limited, Plasma
-ACBL / Bleeding Diathesis Profile, Comprehensive, Plasma
-APROL / Prolonged Clot Time Profile, Plasma
-2INHE / Factor II Inhibitor Evaluation, Plasma
-7INHE / Factor VII Inhibitor Evaluation, Plasma
-10INE / Factor X Inhibitor Evaluation, Plasma
-11INE / Factor XI Inhibitor Evaluation, Plasma
Optical Clot-Based
Reporting Name
General Factor Bethesda Units, PSpecimen Type
Plasma Na CitSpecimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Clinical Information
Significant bleeding can result from the presence of a coagulation factor inhibitor and could be life threatening. Whether the inhibitor is present due to hemophilia or is of an acquired nature, it greatly complicates the treatment process of a decreased factor level. The titer of the inhibitor may determine the mode of treatment. Bethesda units are a standardization to give a uniform definition of an inhibitor.
Reference Values
Only orderable as a reflex. For more information see:
-ALBLD / Bleeding Diathesis Profile, Limited, Plasma
-ACBL / Bleeding Diathesis Profile, Comprehensive, Plasma
-APROL / Prolonged Clot Time Profile, Plasma
-2INHE / Factor II Inhibitor Evaluation, Plasma
-7INHE / Factor VII Inhibitor Evaluation, Plasma
-10INE / Factor X Inhibitor Evaluation, Plasma
-11INE / Factor XI Inhibitor Evaluation, Plasma
≤0.5 Bethesda Units
Interpretation
An interpretive report will be provided when testing is complete.
Cautions
No significant cautionary statements
Clinical Reference
1. Biggs R, Bidwell E. A method for the study of antihemophiliac globulin inhibitors with reference to six cases. Br J Haematol. 1959;5:379-395
2. Hoyer LW: Factor VIII inhibitors. In: Hoyer LW, eds. Progress in Clinical and Biological Research. Vol 150. R Alan Liss Inc, 1984:87-98
3. Kasper CK, Aledort L, Aronson D, et al. Proceedings: A more uniform measurement of factor VIII inhibitors. Thromb Diath Haemorrh. 1975;34(2):61
4. Kasper C, Ewing N. Acquired inhibitors of plasma coagulation factors. J Med Tech 1986;38:431-439
5. Kottke-Marchant K, ed: Laboratory Hematology Practice. Wiley Blackwell Publishing; 2012
6. Hoffman R, Benz Jr EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Elsevier; 2018
Method Description
Undiluted patient plasma and serially diluted patient plasma are mixed with an equal volume of normal pooled plasma (NPP). The NPP supplies the factor against which the inhibitor is directed in a known concentration. The patient plasma mixtures, along with a control (Bethesda Pool) of diluted NPP are incubated at 37° C for 2 hours, after which factor activity is measured. The factor activity in the undiluted patient and its serial dilutions are compared to the factor activity recovered in the Bethesda Pool. These values are then used to calculate Bethesda units. One Bethesda unit is defined as the amount of antibody that will destroy 50% of the coagulation factor activity in 2 hours.( Owen CA Jr, Bowie EJW, Thompson JH Jr: Diagnosis of Bleeding Disorders. 2nd ed. Little, Brown and Company; 1975; Meijer P, Verbruggen HW, Spannagi M: Clotting factors and inhibitors: Assays and interpretation. In: Kottke-Marchant K, ed. Laboratory Hematology Practice. Wiley Blackwell Publishing; 2012:435-446)
Day(s) Performed
Monday through FridayReport Available
2 to 5 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
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.CPT Code Information
85335
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| GBETH | General Factor Bethesda Units, P | 13591-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 607434 | General Factor Bethesda Units, P | 13591-3 |