1 to 3 days

Monday through Friday 8:30 am to 4:30 pm. Call 503-494-7383 if STAT.

Oral anticoagulant therapeutic range: 20% to 40%.

Less than 5%.

Two full 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.

Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.

OHSU clinics must cab specimen to the Core Lab, Hatfield Research Center, 9th Floor (room 9D20) if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-7383.

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

For referral testing, submit one tube with 1.0 mL frozen platelet poor citrated plasma.

One full pediatric 1.3 mL LIGHT BLUE top tube, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.

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

59% to 129%
For children less than 6 months, see link to published reference ranges (Opens in a new window).

Diagnostic Criteria: Factor X, Chromogenic Assay is indicated to monitor oral anticoagulant therapy in patients with a lupus inhibitor or thrombin inhibitor (argatroban, etc.) + 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 amylodosis. The rare clinical condition (X deficiency) is inherited as autosomal, incompletely recessive. About 25 cases of hereditary factor X deficiency have been reported.

Methodology: Chromogenic

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

Chromogenic Factor 10
Chromogenic Factor X