Test Catalog

Test

Code
B165
Name
FACTOR XI ASSAY
Description

Alternative Names: B165, F11A, FACTOR XI ACTIVITY, PTA, FACTOR ELEVEN ACTIVITY, FACTOR ELEVEN ASSAY, FACTOR 11, HEMOPHILIA C FACTOR
Includes: Factor XI Assay
Sample Type: Citrated Platelet Poor Plasma (PPP), see below for instructions
Preferred Container: Sodium Citrate (Blue Top, 3.2%) Tube
Sample Volume: 2.0 mL
Minimum Volume: 1.0 mL
Handling Instructions: Transfer 2 mL platelet-poor plasma to a Standard Transport Tube.
CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.
Transport Temperature: Critical Frozen
Specimen Stability: Ambient: 4 hours; Refrigerated: Unacceptable; Frozen: 2 weeks
Testing Frequency: Monday, Tuesday, Wednesday, Thursday, Friday, Saturday
Expected Turn Around Time: 3 – 6 Days
Testing Facility: ARUP
CPT Codes: 85270
Ordering Recommendation: Order to diagnose factor XI deficiency (hemophilia C).
Note:
Specimen preparation for PPP:
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. To obtain platelet-poor plasma, immediately centrifuge sample at 1500 RCFs for 15 minutes, then pipette the supernatant plasma and transfer to a plastic tube.
3. Re-centrifuge plasma in the plastic transport tube at 1500 RCFs for 15 minutes to ensure that no red cells are present.
4. Pipette the top two-thirds of the supernatant plasma and transfer to another plastic transfer tube.
5. Immediately freeze the plasma at -20 degrees C or lower for transport. Critical Frozen.
6. When multiple tests are ordered, submit separate tube for this test.
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