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Test ID 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. See Coagulation Profile Comparison in Special Instructions for testing that is performed with each profile.

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 in Special Instructions.

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, ≤-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.


Coagulation Patient Information (T675) in Special Instructions. 

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


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

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 in Special Instructions.



≤0.5 Bethesda Units

Day(s) Performed

Monday through Friday

Report Available

2 to 3 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

See Individual Test IDs

CPT Code Information




LOINC Code Information

Test ID Test Order Name Order LOINC Value
CHF8P Chromogenic FVIII Inhibitor Profile 95121-0


Result ID Test Result Name Result LOINC Value
CH8B Chromogenic FVIII Inhibitor Titer,P 93450-5
606844 Chromogenic FVIII Inhibitor Interp 95122-8
CHF8 Chromogenic FVIII, P 49865-9
606865 Reviewed by 18771-6