Chromogenic Factor VIII
General Information
Lab Name
Chromogenic Factor VIII
Lab Code
CHRF8
Epic Name
Factor VIII Activity, Chromogenic
Description
Chromogenic Factor 8 Activity is a photometric assay used to identify factor VIII deficiency as well as for monitoring coagulation factor replacement therapy of certain extended half-life coagulation factor replacements. This assay uses bovine-based factor reagents and can be used to measure native factor VIII levels in the presence of emicizumab (Hemlibra). Chromogenic Factor 8 activity in combination with C-reactive protein can also be used to evaluate risk for venous thormbosis.
Synonyms
Chromogenic Factor 8 Activity, Refacto Assay (Recombinant F8)
Interpretation
Method
Optical Chromogenic (2-stage) bovine-based assay
Reference Range
Units: %
| Female | Male | ||
|---|---|---|---|
| Age | Range | Age | Range |
| 0- | 50-200 | 0- | 50-200 |
Effective date: 08/17/2020
Interferences and Limitations
Chromogenic FVIII level may be falsely decreased in the presence of direct factor Xa inhibitors such as rivaroxaban (Xarelto), apixaban (Eliquis) and edoxaban (Savaysa). There is no effect from up to 2.0 IU/mL of unfractionated heparin or low molecular weight heparin in the plasma. Certain extended half-life formulations of recombinant factor VIII may give unreliable results with various Factor VIII assays.
Ordering & Collection
Specimen Type
Collection
3 or 5 mL BLUE TOP (CITRATE) tube
Forms & Requisitions
Outside clients should fill and submit Coagulation Patient Clinical History Form: Coagulation Patient Clinical History Form
Approval Required
**Laboratory Medicine resident's approval is required for hospital inpatients and patients in Emergency Department.**
Handling Instructions
The Laboratory MUST process specimen, within 4 hrs of blood collection.
Quantity
requested: entire specimen
Processing
UW-MT Instructions: Take specimen to UW-MT Coag lab for processing. Coag tech will freeze plasma sample for transport to HMC Coag.
HMC Instructions: Take specimen to HMC Coag lab for processing.
Outside Laboratory: 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.
Performance
LIS Dept Code
Coagulation (COAG)
Performing Location(s)
| HMC |
Coagulation
206-520-4600 325 9th Ave, Rm # GWH-47, Seattle, WA 98104-2420 |
|---|
Frequency
Run Monday and Thursday. Reported by end of day.
Available STAT?
Yes. Contact Lab Medicine Resident for approval.
Billing & Coding
CPT codes
85130
LOINC
Interfaced Order Code
UOW891
Interfaced Result Code
UOW891