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Epic Code LAB1230831 Chromogenic Factor VIII Activity

Test Name Alias

Factor VIII chromogenic | Factor Assay | Factor 8 | Factor VIII | Hemophilia A

Interface Order Alias


Quick Collect


Clinical Information

The Chromogenic Factor VIII activity assay is useful for monitoring coagulation factor replacement therapy of selected extended half-life coagulation factor replacements and  Emicizumab therapy, a recombinant, monoclonal antibody that restores the function of the missing activated factor VIII by bridging FIXa and FX .  The action of Emicizumab interferes with all APTT clot based and human chromogenic based assays, leading to an overestimation of Factor VIII activity.  As such, the bovine based Chromogenic Factor VIII assay is recommended. 


The Chromogenic Factor VIII activity also assists in the diagnosis of hemophilia A using a 2-stage assay, particularly when the 1-stage assay is normal.

Collection Instructions

Specimen Collection: Blood

Container(s): Blue top (3.2% Na. Citrate) 2.7 mL or 1.8 mL tube

Preferred Volume to Collect: 2.7 mL (full tube)

Minimum Volume to Collect: 1.8 mL (full tube)

Neonate Volume to Collect: 1.8 mL (full tube)

Capillary collect ok? No

Microtainer acceptable: No


Collection Instructions:

  • Detailed instructions (link): Anticoagulant Correction for High Hematocrit

  • Detailed instructions (link): Blue Citrate Tube

  • Tube must be full. Do not over fill or under fill; look for the fill indicator lines.

  • Gently invert 8 - 10 times to mix anticoagulant with blood.
  • Specimen should be processed within 1 hour – See Processing Instructions below.
  • +(1)S10/POx3/F


Processing Instructions (Laboratory, Outpatient or Off-site collection)


  • Processed Specimen: Platelet Poor Plasma
  • Centrifuge/Spin: Yes
  • Aliquot: Yes
  • Processing Instructions:
    • Centrifuge and remove plasma within 1 hour of collection.
    • Separate plasma into 2-3 aliquots, minimum of 0.5 mL each.
    • Freeze aliquots in plastic transport tubes immediately.
  • Minimum volume: 1.0 mL of aliquoted plasma
  • Transport Temperature:
    • Ambient (up to 1 hour in whole blood state)
    • Frozen (plasma only >1 hour)

Lab Staff Instructions

Instructions for Lab Staff 

Rejection Criteria

  • Hemolysis
  • Frozen plasma aliquot arrives thawed

Specimen Stability

Ambient: 1 hour in whole blood state

Frozen: 2 months (Aliquoted plasma)

Laboratory Retention: 2 months

Test Frequency

Available Monday through Friday, usual turn-around time 1 - 4 days

Reference Range

70% - 150%

Critical Values Table

Performing Department


Performing Department Laboratory Location

Corewell Health Reference Laboratory, Grand Rapids, MI


For photometric determination of Factor VIII activity in human plasma. 



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