Orderable EAP code:

LAB00684

Billable EAP Codes:

80001122 x 1

CPT Codes:

85260 x 1

Lab Section:

Hemostasis and Thrombosis

Turnaround Time:

1 to 3 days

Test Schedule:

Monday, Wednesday, Friday

Units:

%

Interpretation:

Oral anticoagulant therapeutic range: 20% to 40%.

Critical Values:

≤ 10%

Specimen Requirements:

Two full 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate. Specimens must be processed and frozen within 2 hours of specimen collection.

Send 2- 1mL aliquots of platelet poor plasma, samples must remain frozen during storage and shipment. 

Stability is 14 days at -20 C or at –70°C for up to 12 months.

Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.

Pediatric Specimen Requirements:

One full pediatric 1.3 mL LIGHT BLUE top tube, 3.2% sodium citrate. Specimens must be processed and frozen within 2 hours of specimen collection. 

Send 1 600 uL aliquot of platelet poor plasma, samples must remain frozen during storage and shipment. 

Stability is 14 days at -20 C or at –70°C for up to 12 months.

For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.

Reference Range:

59% to 130%

Therapeutic range: Patient on warfarin anticoagulant therapy: 20-40%

INR of 2.0 - 3.5 correlates with a Factor X activity of 20-40%.

Comments:

Diagnostic Criteria: Factor X, Chromogenic Assay is indicated to monitor oral anticoagulation therapy in patients with a lupus inhibitor or thrombin inhibitor (argatroban, ect) + coumadin. This method is not affected by the lupus inhibitor or by therapeutic heparin levels. 

Assay performed to document congenital and acquired factor deficiency. (Order Factor X, chromogenic if patient on argatroban, lepirudin or other thrombin inhibitors).

Acquired deficiencies occur with significant hepatic dysfunction and with oral anticoagulant (coumarin) therapy. Factor X levels are most frequently used to monitor oral anticoagulant therapy in patients with lupus inhibitors. Factor X deficiency may be associated with primary systemic amyloidosis. The rare clinical condition (X deficiency) is inherited as autosomal, incompletely recessive. About 25 cases of hereditary factor X deficiency have been reported. 

High doses of standard heparin (greater than 1.0 U/mL) may interfere with PT mixing study. Anti-Xa agents such as Rivaroxaban may also interfere with PT mixing studies. Clinical correlation is advised. 

Methodology: Chromogenic

This test was developed and its performance characteristics determined by OHSU laboratories. Although the testing kit has been approved by the US Food and Drug Administration (FDA), the use of this kit on the testing platform used at OHSU has not been approved by the FDA. However, the FDA does not require this process to go through FDA review. This test is used for clinical purposes. It should not be regarded as investigational or for research. The laboratory is certified under the Clinical Laboratory Improvement Amendments (CLIA) as qualified to perform high complexity clinical laboratory testing.

Synonyms:

Activity

Chromogenic Factor 10

Chromogenic Factor X