Laboratory Services

Factor VIII Activity

Print this page

Updated Test Information:

Test Description
Factor VIII Activity
Synonym(s)

F8, Factor 8, Factor VIII, UOW1504

Test ID
F8
General Information

Clinical assay interference and limitations: Patients on hirudin (Refludan), bivalrudin (Angiomax), Dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis), edoxaban (Savaysa) and argatroban (Novastan) may show prolonged clotting times. This may cause an under- estimation of the factor concentrations. Emicizumab (Hemlibra) will affect all PTT-based assays and will overestimate the factor concentrations. Certain extended half-life formulation of recombinant Factor VIII may give unreliable results with various Factor VIII assays.

Container Type

3 or 5 mL Blue Top (Citrate) Tube

Specimen Type

Plasma

Specimen Requirements

The Laboratory MUST process specimen, within 4 hrs of blood collection.

Specimen Collection / Processing Instructions

Centrifuge for 10 minutes, remove plasma & re-spin plasma for another 10 minutes. Decant & Freeze plasma (minimum 1.0 mL) @ -20°C to -80°C. Send frozen on dry ice.

Department (code)

Coagulation

Methodology

Stago STA Clottable PTT-based Factor Assay

Testing Schedule

Monday - Friday

CPT Code(s)

85240

Reference Range

Units: %


Male/Female:    50-200
STAT Orderable (Y/N)

Yes

Performing Lab

UW

LOINC Code(s)

3209-4