Test Directory
Factor VIII (8) Activity
Justification
Factor VIII (anti-hemophilic factor) is present in the liver, spleen, kidneys, and lymphocytes. In the plasma, Factor VIII circulates in a complexed form with von Willebrand factor, attached by a non-covalent linkage.
Hemophilia A is characterized by a congenital deficiency of Factor VIII, and inherited in an X-linked recessive manner. The severity of the disorder depends on the Factor VIII:C level: < 1% (severe hemophilia), 1-5% (moderate hemophilia), 5-25% (mild hemophilia). Deficiencies in Factor VIII may also be acquired secondary to other diseases such as liver disease, disseminated intravascular coagulation (DIC), or the development of a specific factor inhibitor.
Factor VIII is an acute phase reactant and may be increased due to stress, thromboembolic complications, coronary atherosclerosis, renal failure, diabetes, and other conditions.
STAT: < 24 hours (7 days a week)
Clot-based
Draw Tube: Blue Top
Sample Type: Citrated Plasma
Specimen Requirements
Sample Type | Volume Required | Minimum Volume | Stability | |
---|---|---|---|---|
PREFERRED | Citrated Plasma | 1mL | 0.5mL | Frozen (-20C): 2 weeks Frozen (-80C): 6 months |
ALTERNATIVE | - | - | - | - |
REJECTION CRITERIA | Thawed in transit, refrozen or clotted sample |
SPECIAL INSTRUCTIONS | - |
General Information
METHODOLOGY | Clot-based |
STAT TAT | < 24 hours (7 days a week) |
STAT TAT Performance | > 90% of results released in 24 hours 7 days a week |
ROUTINE TAT | < 3 days (M-F) |
ALTERNATIVE NAMES | Anti-Hemophilic Factor, F8, FVIII, clottable F8 |
DESCRIPTION | This is a clot-based assay for the determination of Factor VIII Activity level in citrated plasma. Patient sample at three different dilutions is mixed with Factor VIII Deficient plasma containing normal levels of all other factors, such that the resulting activated Partial Thromboplastin Time is dependent only on the level of Factor VIII present in the patient sample. This value is compared to a reference curve generated from calibrators with known levels of Factor VIII Activity. |
LIMITATIONS | - |
NORMAL RANGE | 50-149% |
ASSOCIATED TESTING | - |
REFERENCES | - |
SAMPLE REPORT | Upon request |
NEW YORK STATE APPROVED | No |
Test Codes
ORDER CODE | P3053 |
CPT CODE | 85240 |
LOINC CODE | 3209-4 |