1 to 3 days

Monday through Friday 8:30 am to 4:30 pm. Call 503-494-8445 if STAT.

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.

65% to 150%
For children less than 6 months, see link to published reference ranges (Opens in a new window).

Assay to document Factor XI deficiency. Homozygous patients have bleeding symptoms with post-trauma/post-surgical hemorrhage, epistaxis, hematuria, and menorrhagia. Excessive postpartum hemorrhage is especially common. Severity of bleeding does not always correlate with the plasma level of factor XI. This may relate in part to the mechanism of activation of factor XI. Heterozygotes are asymptomatic. Homozygotes have prolonged whole blood clotting time and APTT. Prothrombin time, thrombin time, bleeding time, platelet count, and platelet function tests are normal.

Avoid warfarin (Coumadin) therapy for 2 weeks and heparin therapy for 2 days prior to test.

Methodology: APTT based clotting method.

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.
 

Factor 11
Factor 11A
Factor XI
FXIA