The Hemostasis Laboratory is offering a new test, a chromogenic factor X assay. This test is to be used exclusively in the monitoring of coumadin therapy in patients with a lupus anticoagulant. The advantage of this test is there are no phospholipids in any of the testing substrates. The therapeutic reference range is 11-42%. The test should be collected in a blue top tube (citrated plasma). Testing is done Monday-Friday from 0800 – 1630. Any questions, contact Nancy Rosenthal, MD, at extension 4-8751.