Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

F_9
9065
FACTV
9054
disorders, certain antibiotic therapies, some malignancies, and old age. Inhibitors of factor VIII coagulant
activity are the most commonly occurring of the specific factor inhibitors.
Useful For: Detection and quantitation of inhibitor to factor II
Interpretation: Normally, there is no inhibitor, ie, negative. If the screening assays indicate the
presence of an inhibitor, it will be quantitated and reported in Bethesda (or equivalent) units.
Reference Values:
FACTOR II ACTIVITY ASSAY
Adults: 75-145%
Normal, full-term newborn infants or healthy premature infants may have decreased levels (> or
=25%) which may remain below adult levels for > or =180 days postnatal.*
*See Pediatric Hemostasis References in Coagulation Studies in Special Instructions.
FACTOR II INHIBITOR SCREEN
Negative
Clinical References: 1. Feinstein DI: Acquired inhibitors of blood coagulation. In Hematology:
Basic Principles and Practice. Edited by R Hoffman, EJ Benz Jr, SJ Shattil, et al. New York,
Livingstone Press, 1991, pp 1380-1394 2. Kasper CK: Treatment of factor VIII inhibitors. Prog Hemost
Thromb 1989;9:57-86
Coagulation Factor IX Activity Assay, Plasma
Clinical Information: Factor IX is a vitamin K-dependent serine protease synthesized in the liver
and participates in the intrinsic coagulation pathway. Its biological half-life is 18 to 24 hours.
Congenital deficiency inherited as an X-linked recessive bleeding disorder (hemophilia B). Severe
deficiency ( or =180 days postnatal.*
*See Pediatric Hemostasis References in Coagulation Studies in Special Instructions.
Clinical References: 1. Barrowcliffe TW, Raut S, Sands D, Hubbard AR: Coagulation and
chromogenic assays of factor VIII activity: general aspects, standardization, and recommendations.
Semin Thromb Hemost 2002 Jun;28(3):247-256 2. Franchini M, Lippi G, Favaloro EJ: Acquired
inhibitors of coagulation factors: part II. Semin Thromb Hemost 2012 Jul;38(5):447-453 3. Carcao MD:
The diagnosis and management of congenital hemophilia. Semin Thromb Hemost 2012
Oct;38(7):727-734
Coagulation Factor V Activity Assay, Plasma
Clinical Information: Factor V is a vitamin K-independent protein synthesized in the liver and in
other tissues (endothelium, megakaryocytes/platelets). In its thrombin-activated form (factor Va), it
serves as an essential cofactor in the prothrombinase enzyme complex which converts prothrombin to
thrombin (the prothrombinase complex consists of the enzyme, activated factor X, factor Va cofactor, a
phospholipid surface, and calcium). Deficiency of factor V may cause prolonged prothrombin time and
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