Inactivated/Replace Test
Effective Date
05/05/2026
Included in Report
Replacement Test
F8INH – “Factor VIII Inhibitor” replaced by F8AIN – “Factor VIII Activity with Inhibitor Reflex”
Back to Test UpdatesInactivated/Replace Test
Inactivated Test Details
Mnemonic
F8INH
Ordering Code
3502730
CPT-4 Codes(s)
85730, 85732 x 3, 85240, 85335
Replacement Test Details
Mnemonic
F8AIN
Ordering Code
3500008
CPT-4 Codes(s)
85240, plus 85240 X 2, 85335 if reflexed to Inhibitor, at additional cost
Turnaround Time
7 - 9 days
Performed
Sunday - Saturday
Legacy Code
F8AIN
Example Report
Specimen Information
Patient Preparation
The patient should not be on anticoagulant therapy. Avoid warfarin (Coumadin®) therapy for two weeks prior to the test and heparin, direct Xa and thrombin inhibitor therapies for about three days prior to testing. Do not draw from an arm with a heparin lock or heparinized catheter.
Collect
Light blue sodium citrate
Specimen Preparation
See Coagulation Test Collection guide found under Resources/Interpretation Guides and Forms for coagulation test collection instructions. Send 2.0 mL platelet-poor plasma in a screw capped plastic vial. CRITICAL FROZEN.
Special Instructions: If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted.
Special Instructions: If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted.
Minimum Volume
1.0 mL
Transport Temperature
Critical frozen
Rejection Criteria
Severe hemolysis, clotted specimen, specimen diluted with IV fluids; thawed samples
Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 28 days (Stable X 3 Freeze/thaw cycles)
Refrigerated: Unacceptable
Frozen: 28 days (Stable X 3 Freeze/thaw cycles)
Methodology
Clot Based Methodology
Reference Range
Factor VIII Activity: 57-177 %
Factor VIII Inhibitor (Bethesda units): 0.0-0.7 BU
Factor VIII Inhibitor (Bethesda units): 0.0-0.7 BU
Performing Laboratory
LabCorp
New York DOH Approval Status
Yes