Factor IX Antigen

Test Code
91053

CPT Codes
85250

Preferred Specimen
1 mL frozen platelet-poor plasma collected in a 3.2% sodium citrate (light blue-top) tube

Minimum Volume
0.5 mL

Instructions
Platelet poor plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic screw-cap vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic screw-cap vial. Plasma must be free of platelets (<10, 000/mcL). Freeze immediately and ship on dry ice. Do not thaw.

Transport Container
Plastic screw-cap vial

Transport Temperature
Frozen

Specimen Stability
Room temperature: 4 hours
Refrigerated: 48 hours
Frozen (-20°C): 30 days
Frozen (-70°C): 6 months

Methodology
Immunoassay (IA)

Setup Schedule
Set up: As needed: at least 1x/month; Report available: 2-31 days

Report Available
31 days

Reference Range
0.64-1.29 IU/mL

Clinical Significance
The laboratory diagnosis of factor IX deficiency typically involves quantitative determinations of functional activity of factor IX. An ELISA for factor IX antigen may be used in conjunction with functional assays in the area of gene therapy, assessment of factor IX concentrates, determination of carrier status as well as distinguishing those patients with cross-reactive material (i.e. low functional activity but near normal antigen levels of factor IX).

Performing Laboratory
Quest Diagnostics Nichols Inst San Juan Capistrano
33608 Ortega Highway
San Juan Capistrano, CA 92690-6130



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.