Factor IX Activity, Clotting

Test Code

30774

CPT Codes
85250<br>Limited Access Code

Preferred Specimen

1 mL 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 WBS/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcL). Freeze immediately and ship on dry ice.

Refer to Quest Diagnostics Directory of Services under Specimen Collection section, Coagulation Testing for further information on specimen processing.

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen -20° C: 14 days
Frozen -70° C: 1 year

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Hemolyzed specimens

Methodology
Photometric Clot Detection

Setup Schedule

Set up: Mon-Fri; Report available: Next day

Reference Range

60-160 % of normal

Clinical Significance

This assay measures the activity of coagulation FIX in plasma. Individuals with FIX activity <50% have hemophilia B, a condition marked by episodes of excessive or unexplained bleeding that affects all races and ethnic groups equally. Indications for FIX testing include a personal history of excessive or unexplained bleeding and family history of hemophilia B [1,2].
FIX deficiency is an X-linked condition that mainly affects boys and men, though a small percentage of those affected are women, who may be asymptomatic carriers or have very mild symptoms. Therefore, FIX testing may be appropriate for pregnant women with a family history of hemophilia B. Although FIX deficiency is generally considered an inherited
condition, approximately one-third of cases are caused by spontaneous genetic mutations. [1,2] Severe cases of hemophilia B (FIX<1%) may become evident in early infancy, when boys bleed excessively after circumcision. However, moderate (FIX 6% to 49%) and mild (FIX 1% to 5%) cases may remain undiagnosed until excessive bleeding is noted following trauma, injury, or surgery [1,2].

References
1. AACC. Coagulation factors. https://labtestsonline.org/tests/coagulation-factors. Accessed October 2, 2019.
2. National Hemophilia Foundation. Hemophilia V. https://www.hemophilia.org/Bleeding-Disorders/Types-of-Bleeding-Disorders/Hemophilia-B. Accessed October 2, 2019.

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.