FACTOR VIII INHIBITOR EVALUATION

General Information

HLAB/HOL Code: FAC8I
UPHSM LIS Test #: 7067
Schedule: Monday - Friday, Varies
Testing Time: 2-3 Days
Testing Lab: Mayo Labs

Specimen Info
Only 1 specimen type required, unless otherwise specified

Volume: 3 mL in 3, 1 mL aliquots Plasma
Temperature: Frozen
Tube Type: 1 Light Blue Citrate tube
Collection Info:
1. Specimen must be drawn prior to factor replacement therapy.
2. Spin down, remove plasma, and spin plasma again.
3. Freeze specimens immediately at < or = minus 40 degrees C, if possible.
4. Send specimens in the same shipping container.

Additional Information:
1. Double centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
2. If priority specimen, mark request form, give reason, and request a call back.
3. Each coagulation assay requested should have its own vial.

Methods

Activated Partial Thromboplastin Clot Based Assay

Clinical Utilities

Detecting the presence and titer of a specific factor inhibitor directed against coagulation factor VIII.
Factor VIII inhibitors are IgG antibodies directed against coagulation FVIII that typically result in development of potentially life-threatening hemorrhage.  These antibodies may develop in 1 of 4 different patient populations:
-Patients with congenital FVIII deficiency (hemophilia A) in response to therapeutic infusions of factor VIII concentrate
-Elderly nonhemophiliac patients (not previously factor VIII deficient)
-Women in postpartum period
-Patients with other autoimmune illnesses

CPT Codes

85240-Factor VIII activity assay
85335-Bethesda titer (if appropriate)
85335-Factor VIII inhibitor screen (if appropriate)
85390-26-Special coagulation interpretation (if appropriate)


* The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding
is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Reference Range

FACTOR VIII ACTIVITY ASSAY
Adults: 55-200%
Normal, full-term newborn infants or healthy premature infants usually have normal or elevated factor VIII.*

FACTOR VIII INHIBITOR SCREEN

Negative