Test ID 2INHE Factor II Inhibitor Evaluation, Plasma
Ordering Guidance
This test is for factor II inhibitors only. If the presence or type of inhibitor is unknown, order APROL / Prolonged Clot Time Profile, Plasma first, except for when screening studies are needed for patients with known hemophilia A or B.
Shipping Instructions
Send all vials in the same shipping container.
Necessary Information
If priority specimen, mark request form, give reason, and request a call-back.
Specimen Required
Patient Preparation:
1. Patient must not be receiving Coumadin (warfarin) or heparin therapy
2. Fasting preferred
Specimen Type: Platelet-poor plasma
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vials
Specimen Volume: 3 mL in 3 plastic vials each containing 1 mL
Collection Instructions:
1. Specimen must be collected prior to factor replacement therapy.
2. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.
3. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.
4. Aliquot 1-2 mL of plasma into 3 separate plastic vials leaving 0.25 mL in the bottom of centrifuged vial.
5. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, ≤-40° C.
Additional Information:
1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
2. Each coagulation assay requested should have its own vial.
Useful For
Detection and quantitation of inhibitor to factor II
This test is not useful for the detection of a lupus-like circulating anticoagulant inhibitor, a nonspecific circulating anticoagulant, or other inhibitors that are not specific for coagulation factors.
Profile Information
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
2INHT | FII Inhib Profile Tech Interp | No | Yes |
F_2 | Coag Factor II Assay, P | Yes | Yes |
Reflex Tests
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
2AINH | FII Inhib Profile Prof Interp | No | No |
F2_IS | Factor II Inhib Scrn | No | No |
GBETH | General Factor Bethesda Units, P | No | No |
Testing Algorithm
Testing begins with coagulation factor II activity assay with dilutions to evaluate assay inhibition; if the factor II activity assay is normal or increased, a technical interpretation will be provided. If the factor II activity assay is decreased, an inhibitor screen will be performed at an additional charge to look for specific factor II inhibition and a professional interpretation will be provided. If specific inhibition is apparent, the titer of the inhibitor will be determined.
Special Instructions
Method Name
Optical Clot-Based
Reporting Name
Factor II Inhib Profile, PSpecimen Type
Plasma Na CitSpecimen Minimum Volume
2 mL in 2 plastic vials, 1 mL each
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Plasma Na Cit | Frozen | 14 days |
Reference Values
FACTOR II ACTIVITY ASSAY
Adults: 75-145%
Normal, full-term newborn infants or healthy premature infants may have decreased levels (≥25%) which may remain below adult levels for ≥180 days postnatal.*
*See Pediatric Hemostasis References in Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.
Day(s) Performed
Monday through FridayReport Available
1 to 3 daysPerforming Laboratory

Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
85390 - Factor II Tech Interp
85210 - Factor II
85335 - Factor inhibitor (if appropriate)
85335 - Bethesda units (if appropriate)
85390 - Factor II Professional Interp (if appropriate)
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
2INHE | Factor II Inhib Profile, P | 96455-1 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
F_2 | Coag Factor II Assay, P | 3289-6 |
2INHT | FII Inhib Profile Tech Interp | 69049-5 |
Forms
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.