Basic Laboratory Tests of Hemostatic Function - Factor Assays

How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 148 CE courses, most popular
$95Add to cart
Pick Your Courses
Up to 8 CE hours
$50Add to cart
Individual course$20Add to cart
Need multiple seats for your university or lab? Get a quote
The page below is a sample from the LabCE course Fundamentals of Hemostasis. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Fundamentals of Hemostasis (online CE course)
Basic Laboratory Tests of Hemostatic Function - Factor Assays

Factor Assays can be used to determine the cause of an unexpected, prolonged PT or APTT. They are performed after mixing studies have been run, because factor assays are able to identify specific factor deficiencies or inhibitors.
Think of mixing studies as being the screening test, while factor assays are confirmatory tests for specific factor deficiencies.
The test itself is involves performing a PT and APTT, except that plasma known to be deficient in a specific factor type is combined with the patients plasma, comparing the resultant time to a standard curve. The percent of activity, and amount of correction with normal plasma determines the specific factor deficiencies.