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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