Factor IX Activity with Reflex to Bethesda Quantitative, Factor IX
Ordering Recommendation
Order to diagnose factor IX deficiency, detect factor IX inhibitors, and monitor factor IX replacement therapy.
Electromagnetic Mechanical Clot Detection
1-3 days  
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
Lt. blue (sodium citrate). Refer to Specimen Handling at aruplab.com for hemostasis/thrombosis specimen handling guidelines.  
Specimen Preparation
Transfer two 3 mL aliquots of platelet-poor plasma to two ARUP Standard Transport Tubes. (Min: 2 mL/each)  
Storage/Transport Temperature
CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.  
Unacceptable Conditions
Serum. EDTA plasma or hemolyzed specimens.  
For hemophiliacs: Note dose, date, and time of last factor IX concentrate infusion.  
Ambient: 4 hours; Refrigerated: Unacceptable; Frozen: 2 weeks  
Reference Interval
Test Number Components Reference Interval
0030100Factor IX, Activity 1-​4 days: 15-​91%
5-​29 days: 15-​91%
30-​89 days: 21-​81%
90-​179 days: 21-​113%
180-​364 days: 36-​136%
1-​5 years: 47-​104%
6 years: 63-​89%
7-​9 years: 70-​133%
10-​11 years: 72-​149%
12-​13 years: 73-​152%
14-​15 years: 80-​161%
16-​17 years: 86-​176%
18 years and older: 78-​184%
 Bethesda Quantitative, Factor IX Effective May 19, 2014
0.4 BU or less
Interpretive Data
If Factor IX activity is 20% or less, then Bethesda Quantitative, Factor IX will be added. Additional charges apply.
CPT Code(s)
85250; if reflexed, add 85335
Component Test Code*Component Chart NameLOINC
0030033Bethesda Quantitative, F9 
0030100Factor IX, Activity3187-2
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • Bethesda Quantitative Factor IX
  • Coagulation Factor IX Inhibitor, Plasma
  • Factor IX Inhibitor Concentration
  • Factor IX Inhibitor, Quantitative
  • Factor IX, Activity