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HelpTest Code F8IS Coagulation Factor VIII Inhibitor Screen, Plasma
Specimen Required
Only orderable as a reflex. For more information see:
8INHE / Factor VIII Inhibitor Evaluation, Plasma
ALUPP / Lupus Anticoagulant Profile, Plasma
ALBLD / Bleeding Diathesis Profile, Limited, Plasma
APROL / Prolonged Clot Time Profile, Plasma
AVWPR / von Willebrand Disease Profile, Plasma
For more information see Coagulation Guidelines for Specimen Handling and Processing.
Method Name
Only orderable as a reflex. For more information see:
8INHE / Factor VIII Inhibitor Evaluation, Plasma
ALUPP / Lupus Anticoagulant Profile, Plasma
ALBLD / Bleeding Diathesis Profile, Limited, Plasma
APROL / Prolonged Clot Time Profile, Plasma
AVWPR / von Willebrand Disease Profile, Plasma
Optical Clot-Based
Reporting Name
Coag Factor VIII Assay Inhib Scrn,PSpecimen Type
Plasma Na CitSpecimen Minimum Volume
2 mL
Specimen 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
Specific factor inhibitors are antibodies that are found most often in response to the use of factor VIII concentrate by patients congenitally deficient in factor VIII (hemophilia A). Factor VIII inhibitors can also develop in non-hemophiliac patients (not previously factor VIII deficient), most commonly in the following: the elderly, postpartum patients, and patients with autoimmune disease. Testing will include coagulation factor VIII activity assay with dilutions to evaluate assay inhibition, and if the factor VIII assay activity is decreased, an inhibitor screen to look for specific factor VIII inhibition. If specific inhibition is apparent, it will be titered.
Reference Values
Only orderable as a reflex. For more information see:
8INHE / Factor VIII Inhibitor Evaluation, Plasma
ALUPP / Lupus Anticoagulant Profile, Plasma
ALBLD / Bleeding Diathesis Profile, Limited, Plasma
APROL / Prolonged Clot Time Profile, Plasma
AVWPR / von Willebrand Disease Profile, Plasma
Negative
Day(s) Performed
Monday through Friday
Report Available
1 to 3 daysSpecimen Retention Time
7 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 |
|---|---|---|
| F8IS | Coag Factor VIII Assay Inhib Scrn,P | 3206-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 7289 | Coag Factor VIII Assay Inhib Scrn,P | 3206-0 |
Useful For
Detecting the presence of a specific factor inhibitor directed against coagulation factor VIII
Interpretation
When testing is complete, if factor activity results fall within clinically normal ranges, an interpretive comment will be provided noting that inhibitor testing was not indicated and, therefore, not performed. If factor activity indicates the performance of inhibitor screen testing, an interpretive comment will be provided noting the presence or absence of a factor VIII inhibitor.
Cautions
Occasionally, a potent lupus-like anticoagulant may cause false-positive results for a specific factor inhibitor (eg, factor VIII or IX).
Clinical Reference
1. Bowie EJW, Thompson JH Jr, Didisheim P, Owen CA Jr. Mayo Clinic Laboratory Manual of Hemostasis. WB Saunders Company; 1971:111-115
2. Kasper CK. Treatment of factor VIII inhibitors. Prog Hemost Thromb. 1989;9:57-86
3. Peerschke EI, Castellone DD, Ledford-Kraemer M, et al. Laboratory assessment of FVIII inhibitor titer. Am J Clin Pathol. 2009;131(4):552-558
4. Pruthi RK, Nichols WL. Autoimmune factor VIII inhibitors. Curr Opin Hematol. 1999;6(5):314-322
5. Laboratory Hematology Practice. In: Kottke-Marchant K, ed. Wiley Blackwell Publishing; 2012
6. Hematology: Basic Principles and Practice. In: Hoffman R, Benz EJ Jr, Silberstein LE, ed. 7th ed. Elsevier; 2018
Method Description
The factor VIII inhibitor screen is performed on the Instrumentation Laboratory ACL TOP. The assay consists of measuring the factor VIII activity (activated partial thromboplastin time based assay) before and after incubation of a mixture of normal plasma and patient's plasma for 1 hour at 37° C. Interpretation of the presence or absence of the indication of a factor VIII inhibitor is determined by comparing the factor VIII activity results and the calculated expected values.(Owen CA Jr, Bowie EJW, Thompson JH Jr. The Diagnosis of Bleeding Disorders. 7nd ed. Little Brown and Company; 1975:143-145; Meijer P, Verbruggen HW, Spannagi M. Chapter 33: Clotting factors and inhibitors: Assays and Interpretation. In: Kottke-Marchant K, ed. Laboratory Hematology Practice. Wiley Blackwell Publishing; 2012:435-446)
Disease States
- Hemophilia A