Chromogenic Factor VIII Activity Assay, Plasma
Use
The Chromogenic Factor VIII Activity Assay is useful for monitoring coagulation factor replacement therapy, specifically for extended half-life factor replacements. It is particularly significant in diagnosing hemophilia A when a patient shows normal results on the one-stage assay. This assay quantitatively measures the function of Factor VIII in blood plasma using a two-stage chromogenic method, making it an essential tool in both diagnosis and management of hemophilia A. It is recommended as part of the initial workup for hemophilia A, following recent guidelines, regardless of the 1-stage assay results.
Special Instructions
For FVIII inhibitor testing, call 800-533-1710 within 7 days to ensure an adequate plasma sample is available. Double-centrifuged specimens are critical for accurate results due to the potential for platelet contamination. Coagulation testing is complex and a consultation is recommended to correlate laboratory results with clinical findings.
Limitations
The assay results may be affected by excess heparin and improper specimen collection, such as contamination by IV lines or collecting specimens in EDTA instead of citrate. Inconsistent results can occur in some hemophilia patients when comparing the one-stage and chromogenic assays. Specimens must be handled and stored properly to avoid false readings due to platelet contamination or degradation of clotting factors.
FDA ApprovedNew York Approved
Methodology
Chromogenic
Biomarkers
LOINC Codes
- 49865-9
- 49865-9
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.5 mL
Container
Plastic vial
Collection Instructions
1. Specimen must be collected prior to factor replacement therapy. 2. Centrifuge and transfer plasma into a plastic vial, centrifuge again. 3. Aliquot plasma into plastic vial, freeze immediately at ideally -40 degrees C.
Causes for Rejection
IV heparin contamination
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |