Factor VIII Inhibitor Evaluation, Plasma
Use
Detects the presence and titer of specific factor inhibitors directed against coagulation factor VIII. It is useful for diagnosing factor VIII inhibitors, which are IgG antibodies typically resulting in potentially life-threatening hemorrhage. Patients with congenital factor VIII deficiency (hemophilia A) may develop these antibodies in response to therapeutic infusions of factor VIII concentrate. Nonhemophiliac adult patients, postpartum women, and patients with autoimmune illnesses may also develop these inhibitors.
Special Instructions
This test is specifically for factor VIII inhibitors. For patients with hemophilia A, this is the correct test. If the presence or type of inhibitor is unknown, order APROL / Prolonged Clot Time Profile, Plasma. Ensure fasting for 8 hours preferred, and patient must not be receiving Coumadin (warfarin) or heparin therapy. Specimen must be collected prior to factor replacement therapy.
Limitations
This test is not useful for detecting lupus-like circulating anticoagulant inhibitors or nonspecific circulating anticoagulants. Occasionally, a potent lupus-like anticoagulant may cause false-positive results for specific factor inhibitors (e.g., factor VIII or IX).
New York Approved
Methodology
Other
Biomarkers
LOINC Codes
- 96456-9
- 3209-4
- 69049-5
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
3 mL in 3 plastic vials, each containing 1 mL
Minimum Volume
2 Plastic vials, each containing 1 mL
Container
Polypropylene plastic vials
Collection Instructions
Specimen must be collected prior to factor replacement therapy. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again. Aliquot plasma (1-2 mL per aliquot) into 3 separate plastic vials, leaving 0.25 mL in the bottom of centrifuged vial. Freeze plasma immediately (no longer than 4 hours after collection) at -20 degrees C or, ideally, at -40 degrees C or below.
Patient Preparation
Fasting: 8 hours, preferred but not required. Patient must not be receiving Coumadin (warfarin) or heparin therapy.
Causes for Rejection
Gross hemolysis, Gross lipemia, Gross icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |