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Test Code LABFACTVIIICHROM Factor VIII Activity, Chromogenic

Clinical Information

This two stage assay is useful for detection of Factor VIII activity in patients with lupus anticoagulant or when monitoring specific coaulation factor replacement products that are known to not be measurable by the one stage assay.

 

This method utilizes F:Xa of bovine origin.

Synonym

  • FA8C
  • Factor 8 Activity
  • Factor VIII Clotting
  • Factor VIII Chromogenic

Specimen Required

Preferred Container/Tube: 3.2% Citrate Blue Top - 2.7 mL
Specimen Volume: 2.7 mL
Acceptable Container/Tube: 3.2% Citrate Blue Top - 1.8 mL
Specimen Volume: 1.8 mL
Platelet poor plasma (PPP):
Specimen Volume: 2 - 1 mL aliquots platelet poor plasma (PPP)
Specimen Minimum Volume: 1 - 1 mL aliquot platelet poor plasma (PPP)

Specimen Collection Information

For Outreach, other than OSU Patient Service Centers: Samples must be processed and received frozen/must remain frozen in transit.

For sending frozen plasma specimens, process immediately upon receipt. Centrifuge capped specimen tube in accordance with CLSI H21, at a speed and time required to consistently produce platelet-poor plasma (PPP = platelet count <10 K/uL). Transfer PPP into plastic aliquot tubes, cap and freeze. DO NOT transport until specimens are completely frozen.

Specimen Stability Information

Ambient: 
     Whole blood: 2 hours
      Platelet poor plasma: 2 hours
Frozen: 
      Platelet poor plasma: PPP removed from the cells and frozen at -70°C

Rejected Due To

  • Ambient specimens >2 hours old
  • Clotted specimens
  • Underfilled or overfilled tube
  • Hemolysis

Reference Values

0-4 days: 50-178 % Activity
5-29 days: 50-154 % Activity
30-89 days: 50-157 % Activity
90-179 days: 50-125 % Activity
180-365 days: 50-109 % Activity
1-5 years: 59-142 % Activity
6-10 years: 58-132 % Activity
11-16 years: 53-131 % Activity
17+ years: 50-200 % Activity

Interpretation

<1%: severe hemophilia

1- <5%: moderate hemophilia

5- <40%: mild hemophilia

Cautions

Not indicated for patients receiving rivaroxaban or dabigatran. The performance of this test has not been established in individuals with Von Willebrand disease Type 2M, or for evaluating the potency of FVIII concentrates.

Method Description

Two stage chromogenic assay, measurement at 405nm.

Performing Lab

Clinical Lab UH

Day(s) Performed

Monday through Friday (excludes OSU holidays)

Report Available

Same day/1 day

Reporting Name

Factor VIII Activity, Chromogenic

CPT Code Information

85240

LOINC Code Information

3209-4