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Test Code 7INHE Factor VII Inhibitor Evaluation, Plasma


Ordering Guidance


This test is for factor VII inhibitors only. If the presence or type of inhibitor is unknown, first order APROL / Prolonged Clot Time Profile, Plasma, except for patients with known hemophilia A or B. When screening studies are needed for patients with known hemophilia A or B, order 8INHE / Factor VIII Inhibitor Evaluation, Plasma; or 9 INHE / Factor IX Inhibitor Evaluation, Plasma; respectively.



Shipping Instructions


Send all vials in the same shipping container.



Necessary Information


 



Specimen Required


Specimen Type: Platelet-poor plasma

Patient Preparation:

1. Patient must not be receiving Coumadin (warfarin) or heparin therapy.

2. Fasting preferred

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.

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 or below.

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 coagulation factor VII

 

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
7INHT FVII Inhib Profile Tech Interp No Yes
F_7 Coag Factor VII Assay, P Yes Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
7AINH FVII Inhib Profile Prof Interp No No
F7_IS Factor VII Inhib Scrn No No
GBETH General Factor Bethesda Units, P No No

Method Name

F_7, F7_IS, GBETH: Optical Clot-Based

7INHT: Technical Interpretation

7AINH: Medical Interpretation

Reporting Name

Factor VII Inhib Profile, P

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

2 Plastic vials, each containing1 mL.

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

Clinical Information

Coagulation factor inhibitors arise in patients who are congenitally deficient in a specific factor in response to factor replacement therapy or can occur spontaneously without known cause or in response to a variety of medical conditions including the postpartum state, immunologic disorders, certain antibiotic therapies, some malignancies, and in the older population.

 

Inhibitors of factor VIII coagulant activity are the most commonly occurring of the specific factor inhibitors.

Reference Values

FACTOR VII ACTIVITY ASSAY

Adults: 65-180%

Normal, full-term newborn infants or healthy premature infants may have decreased levels (≥20%) that increase within the first postnatal week but may not reach adult levels for 180 days or more postnatal.*

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

 

FACTOR VII INHIBITOR SCREEN:

Negative

 

GENERAL FACTOR BETHESDA UNITS:
≤0.5 Bethesda Units

Day(s) Performed

Monday through Friday

Report Available

1 to 3 days

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 US Food and Drug Administration.

CPT Code Information

85390

85230

85335 (if appropriate)

85335 (if appropriate)

85390 (if appropriate)

Forms

If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.