Sign in →

Test ID CH8BP Chromogenic Factor VIII Inhibitor Bethesda Profile, Plasma

Advisory Information

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.


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


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

See Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.


Patient Preparation: If drawing sample through a port/line, be sure to waste the appropriate amount prior to collection

Specimen Type: Platelet-poor plasma

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

Submission Container/Tube: Plastic vials

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

Collection Instructions:

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

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

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

4. 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. If a priority specimen, mark request form, give reason, and request a call-back.

3. Each coagulation assay requested should have its own vial.


1. Coagulation Patient Information (T675) in Special Instructions.

2. If not ordering electronically, complete, print, and send a 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). This assay is also useful in patients not on emicizumab (Hemlibra)


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
CH8 Chromogenic FVIII, P Yes Yes
CH8B Chromogenic FVIII Inhibitor Titer,P No Yes
CH8BI Chromogenic FVIII Inhibitor Interp 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 (CH8)

Adults: 55-200%

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) and Time(s) Performed

Monday through Friday; Varies

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
CH8BP Chromogenic FVIII Inhibitor Profile 95121-0


Result ID Test Result Name Result LOINC Value
CH8 Chromogenic FVIII, P 49865-9
CH8B Chromogenic FVIII Inhibitor Titer,P 93450-5
606844 Chromogenic FVIII Inhibitor Interp 95122-8
606865 Reviewed by 18771-6

NY State Approved