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Test Code 5INHE Factor V Inhibitor Evaluation, Plasma


Ordering Guidance


This test is for factor V 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 IX Inhibitor Evaluation, Plasma; or 9 INHE / Factor IX Inhibitor Evaluation, Plasma; respectively.



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


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.


Secondary ID

607426

Useful For

Detection and quantitation of inhibitors against coagulation factor V

 

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
5INHT FV Inhib Profile Tech Interp No Yes
FACTV Coag Factor V Assay, P Yes Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
5AINH FV Inhib Profile Prof Interp No No
5BETH FV Bethesda Units, P No No
F5_IS Factor V Inhib Scrn No No

Testing Algorithm

Testing begins with coagulation factor V activity assay with dilutions to evaluate assay inhibition; if the factor V activity assay is normal or increased, then a technical interpretation will be provided.

 

If the factor V activity assay is decreased, then an inhibitor screen will be performed at an additional charge to look for specific factor V inhibition and a professional interpretation will be provided. If specific inhibition is apparent, the titer of the inhibitor will be determined.

Method Name

FACTV, 5BETH, F5_IS: Optical Clot-Based

5INHT: Technical Interpretation

5AINH: Medical Interpretation

Reporting Name

Factor V 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

Reference Values

FACTOR V ACTIVITY ASSAY

>1 month: 70-165%

<1 month: Normal, full-term and premature newborn infants may have mildly decreased levels (≥30% to 35%) that reach adult levels within 21 days postnatal.

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

 

FACTOR V 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

85220

85335 (if appropriate)

85335 (if appropriate)

85390 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
5INHE Factor V Inhib Profile, P 96458-5

 

Result ID Test Result Name Result LOINC Value
5INHT FV Inhib Profile Tech Interp 69049-5
FACTV Coag Factor V Assay, P 3193-0

Forms

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