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Test Code CHF8P Chromogenic Factor VIII Inhibitor Bethesda Profile, Plasma


Ordering Guidance


This test is indicated for testing for FVIII inhibitors in patients being treated with the specific antibody emicizumab (Hemlibra).

 

This test is for detection of presence of specific inhibitors against factor VIII (FVIII). If the presence or type of inhibitor is unknown, APROL / Prolonged Clot Time Profile, Plasma or ALUPP / Lupus Anticoagulant Profile, Plasma should be ordered first.

 

Multiple coagulation profile tests are available. For testing that is performed with each profile, see Coagulation Profile Comparison.



Shipping Instructions


Send all vials in the same shipping container.



Specimen Required


Specimen Type: Platelet-poor plasma

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Plastic vials

Specimen Volume: 2 mL in 2 plastic vials, each containing 1 mL

Collection Instructions:

1. Specimen must be collected prior to factor replacement therapy.

2. If collecting sample through a port/line, be sure to waste the appropriate amount prior to collection.

3. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing.

4. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

5. Aliquot plasma (1 mL per aliquot) into 2 separate plastic vials leaving 0.25 mL in the bottom of centrifuged vial.

6. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or ideally, at or below -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.


Forms

1. Coagulation Patient Information (T675)

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

Useful For

Detecting the presence and titer of a specific factor inhibitor directed against coagulation factor VIII for patients on emicizumab (Hemlibra)

 

Detecting the presence and titer of an inhibitor directed against factor VIII

 

This test is not useful for detecting the presence of inhibitors directed against other clotting factors and will not detect the presence of lupus anticoagulants.

Profile Information

Test ID Reporting Name Available Separately Always Performed
CH8BI Chromogenic FVIII Inhibitor Interp No Yes
CHF8 Chromogenic FVIII, P Yes Yes
CH8B Chromogenic FVIII Inhibitor Titer,P No Yes

Method Name

Chromogenic

Reporting Name

Chromogenic FVIII Inhibitor Profile

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

See Specimen Required

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
IV heparin contamination Reject

Clinical Information

Factor VIII (FVIII) inhibitors are IgG antibodies directed against coagulation FVIII that typically result in development of potentially life-threatening hemorrhage. These antibodies may be alloimmune: developing in patients with congenital FVIII deficiency (hemophilia A) in response to therapeutic infusions of factor VIII concentrate or autoimmune: occurring in patients without hemophilia (not previously factor VIII deficient) either spontaneously, during pregnancy, or in association with autoimmune diseases.

Reference Values

CHROMOGENIC Factor VIII Activity Assay

Adults: 55.0-200.0%

Normal, full-term newborn infants or healthy premature infants usually have normal or elevated factor VIII.*

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

 

BETHESDA TITER

≤0.5 Bethesda Units

Day(s) Performed

Monday through Friday

Report Available

3 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

See Individual Test IDs

CPT Code Information

CHF8-85130

CH8B-85335

CH8BI-85390-26