Sign in →

Test Code MISC2MOAY8INHE Factor VIII Inhibitor Evaluation, Plasma


Advisory Information


This test is for factor VIII 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 vial

Specimen Volume: 3 mL in 3 plastic vials; each vial 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 plasma (1-2 mL per aliquot) 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.


Secondary ID

607424

Useful For

Detecting the presence and titer of a specific factor inhibitor directed against coagulation factor VIII

 

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
8INHT FVIII Inhib Profile Tech Interp No Yes
F8A Coag Factor VIII Activity Assay, P Yes Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
8AINH FVIII Inhib Profile Prof Interp No No
8BETH FVIII Bethesda Units, P No No
F8IS Coag Factor VIII Assay Inhib Scrn,P No No

Testing Algorithm

Testing begins with coagulation factor VIII activity assay with dilutions to evaluate assay inhibition; if the factor VIII activity assay is normal or increased, a technical interpretation will be provided. If the factor VIII activity assay is decreased, an inhibitor screen will be performed at an additional charge to look for specific factor VIII inhibition and a professional interpretation will be provided. If specific inhibition is apparent, the titer of the inhibitor will be determined.

Method Name

Optical Clot-Based

Reporting Name

Factor VIII Inhib Profile, P

Specimen Type

Plasma Na Cit

Specimen 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

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Reference Values

FACTOR VIII ACTIVITY ASSAY

Adults: 55-200%

Normal, full-term newborn infants or healthy premature infants typically have levels greater or equal to 40%.*

*See Pediatric Hemostasis References in Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.

Day(s) and Time(s) Performed

Monday through Friday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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 U.S. Food and Drug Administration.

CPT Code Information

85390-Factor VIII Tech Interp

85240-Factor VIII activity assay

85335-Bethesda titer (if appropriate)

85335-Factor VIII inhibitor screen (if appropriate)

85390-Factor VIII Professional Interp (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
8INHE Factor VIII Inhib Profile, P In Process

 

Result ID Test Result Name Result LOINC Value
F8A Coag Factor VIII Activity Assay, P 3209-4
8INHT FVIII Inhib Profile Tech Interp 69049-5