Factor XI Activity

Test Code: TD_1475
CPT Code(s): 85270

$79

Test Details

Alternative Name(s)

Factor 11 assay
Factor xi, pta

Test Includes

Factor XI Activity

Methodology

Clot detection

Rejection Criteria

Hemolysis
Thawed samples

Reference Range(s)

“Factor

Specimen Requirements

Preferred Specimen

Citrate (light blue top) tube

Minimum Volume

1 mL frozen plasma

Sample Stability

4 hours room temperature
4 hours refrigerated
2 weeks frozen

Transport Temperature

Critical Frozen

Collection Instructions

1. Fill a light blue top tube as far as vacuum will allow and mix by gentle inversion five to six times. The exact ratio of 1 part sodium citrate to 9 parts blood must be maintained. Inadequate filling of the sample tube will alter this ratio and may lead to inaccurate results.
2. Patients WHO have hematocrit values above 55% should have the anticoagulant adjusted to maintain the 1 to 9 ratio. For further instructions on the collection of platelet-poor plasma for patients with hematocrit value of >55%, please contact CPL Austin customer service.
3. To obtain platelet-poor plasma, immediately centrifuge sample at 1500 RCFs for 15 minutes, then pipette the supernatant plasma and transfer to a plastic transport tube.
4. Re-centrifuge plasma in the plastic transport tube at 15oo RCFs for 15 minutes to ensure that no red cells are present.
5. Pipette the top two-thirds of the supernatant plasma and transfer to another plastic transport tube. Clearly label tube as citrate plasma.
6. Immediately freeze the plasma at -20 degrees C or lower for transport. Critical Frozen (CFZ).
When multiple tests are ordered, submit separate tube for this test.

Alternative Specimen

N/A