Sorted By Test Name - Mayo Medical Laboratories

F_9
9065
FACTV
9054
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
activated partial thromboplastin time. Deficiency may result in a bleeding diathesis. Plasma biological
half-life varies from 12 to 36 hours. Platelets contain 20% to 25% of the factor V in blood. Factor V (also
known as labile factor) is highly susceptible to proteolytic inactivation, with the potential for spuriously
decreased assay results.
Useful For: Diagnosing congenital deficiencies (rare) of coagulation factor V Evaluating acquired
deficiencies associated with liver disease, factor V inhibitors, myeloproliferative disorders, and
intravascular coagulation and fibrinolysis Investigation of prolonged prothrombin time or activated partial
thromboplastin time
Interpretation: See Cautions Acquired deficiencies are much more common than congenital (see
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