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Test ID CH8 Chromogenic Factor VIII Activity Assay, Plasma

Necessary Information

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

Specimen Required

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


Specimen Type: Platelet-poor plasma

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

Submission Container/Tube: Polypropylene vial

Specimen Volume: 1 mL

Collection Instructions:

1. Centrifuge, remove plasma, and centrifuge plasma again.

2. Freeze specimen immediately at ≤-40° C, if possible.

3. Freeze within 4 hours of collection.

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

Monitoring coagulation factor replacement therapy of selected extended half-life coagulation factor replacements


Aiding in the diagnosis of hemophilia A using a 2-stage assay, especially when the 1-stage assay was normal

Testing Algorithm

This assay is indicated in situations where there is a clinical suspicion of hemophilia A diagnosis, but the 1-stage Factor VIII assay is normal. However, recent guidelines also recommend this assay be performed in addition to the 1-stage assay in the initial workup of hemophilia A.


Testing for autoantibodies to FVIII in the presence of a low FVIII activity may be clinically indicated. For adding on FVIII inhibitor, contact Mayo Clinic Laboratories within 7 days to assess if adequate plasma sample is available.


Coagulation testing is highly complex, often requiring the performance of multiple assays and correlation with clinical information. For that reason, we recommend requesting a coagulation consultation.


See Hemophilia Testing Algorithm in Special Instructions.

Method Name


Reporting Name

Chromogenic FVIII, P

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 14 days

Reference Values



Chromogenic Factor VIII activity generally correlates with the one-stage FVIII activity. In full term/premature neonates, infants, children, and adolescents the one-stage FVIII activity* is similar to adults. However, no similar data for chromogenic FVIII activity are available.(Appel JTH 2012;10:2254)


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

Day(s) and Time(s) Performed

Monday through Friday

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 U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
CH8 Chromogenic FVIII, P 49865-9


Result ID Test Result Name Result LOINC Value
CH8 Chromogenic FVIII, P 49865-9

NY State Approved