| Primary Name | Factor IX Assay |
| Synonym | Factor IX Functional Assay |
| Synonym | -- |
| Contraction | FIX |
| UAB Procedure Number | 2500500 |
| CPT Code | 85250 |
| Specimen | Collect one (1) blue-stopper tube (3.2% sodium citrate), filled to specified volume. Do not underfill or overfill. |
| Specimen Management | Note time of collection and time of last treatment if applicable. Centrifuge blue-stopper tube within 1 hour of collection, separate plasma and test or quick-freeze at -70°C. |
| Specimen Accepted | Daily including weekends |
| Test Performed | Monday-Friday. |
| Available Stat? | Pathologist's approval required. |
| Description | Congenital factor IX deficiency, termed hemophilia B, is inherited as a sex-linked recessive and is seen in 1 in 30,000 males. Acquired factor IX deficiency is seen in liver disease, vitamin K deficiency, and Coumadin therapy. Factor IX deficiency is associated with mild to severe bleeding. |
| Reference Interval | 50-150% |
| Critical Value | None |
| Follow-up Test | If an anti-IX inhibitor is suspected, the anti-IX inhibitor titer (Bethesda titer) may be ordered. |
| Associated With | Bleeding disorders |
| Associated With | Vitamin K deficiency |
| Associated With | Liver disease |
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