Chromogenic Factor IX Activity Assay, Plasma
Use
The Chromogenic Factor IX Activity Assay is useful for monitoring coagulation factor replacement therapy, especially with extended half-life replacements. It aids in diagnosing hemophilia B using a 2-stage assay when a 1-stage assay shows normal results. The assay provides accurate classification and monitoring, particularly with new long-acting products, for optimal patient management.
Special Instructions
To order the test, if not done electronically, a Coagulation Test Request form (T753) must be included with the specimen. Double-centrifuged specimens are crucial for accuracy as platelet contamination may cause false results. Separate the plasma and freeze it immediately following specific guidelines for proper handling and processing.
Limitations
Artifactually decreased results can occur due to excess heparin or improper specimen collection through IV devices. While there is expected correlation between 1-stage and chromogenic FIX assays in the normal population, discrepancies may occur using PEGylated recombinant FIX products or within the hemophilia population during factor replacement therapy.
New York Approved
Methodology
Other (Chromogenic)
Biomarkers
LOINC Codes
- 88449-4
- 88449-4
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
Polypropylene vial preferred
Collection Instructions
Centrifuge and transfer all plasma into a plastic vial, centrifuge again, and aliquot the plasma to a separate vial, leaving some plasma in the bottom. Freeze immediately at -20°C or lower, ideally at -40°C or lower.
Causes for Rejection
N/A
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |