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

F_7
9055
F7IS
7809
Coagulation Factor VII Activity Assay, Plasma
Clinical Information: Factor VII is a vitamin K-dependent serine protease synthesized in the liver.
It is a component of the extrinsic coagulation scheme, measured by the prothrombin time. Plasma
biological half-life is about 3 to 6 hours. Deficiency may result in a bleeding diathesis.
Useful For: Diagnosing congenital deficiency of coagulation factor VII Evaluating acquired
deficiencies associated with liver disease, oral anticoagulant therapy, and vitamin K deficiency
Determining degree of anticoagulation with warfarin to correlate with level of protein C Investigation of
a prolonged prothrombin time
Interpretation: Liver disease, vitamin K deficiency, or warfarin anticoagulation can cause decreased
factor VII activity. Heterozygotes generally have levels of < or =50%. Homozygotes have levels usually
or =25%.
Reference Values:
Adults: 65-180%
Normal, full-term newborn infants or healthy premature infants may have decreased levels (> or
=20%) which increase within the first postnatal week but may not reach adult levels for > or =180 days
postnatal.*
*See Pediatric Hemostasis References in Coagulation Studies in Special Instructions.
Clinical References: 1. Girolami A, Scandellari R, Scapin M, Vettore S: Congenital bleeding
disorders of the vitamin K-dependent clotting factors. Vitam Horm 2008;78:281-374 2. Brenner B,
Kuperman AA, Watzka M, Oldenburg J: Vitamin K-dependent coagulation factors deficiency. Semin
Thromb Hemost 2009 Jun;35(4):439-446 3. Mariani G, Bernardi F: Factor VII deficiency. Semin
Thromb Hemost 2009 Jun;35(4):400-406
Coagulation Factor VII Inhibitor Screen, Plasma
Clinical Information: Coagulation factor inhibitors arise in patients who are congenitally deficient
in a specific factor in response to factor replacement therapy, or can occur spontaneously without
known cause or in response to a variety of medical conditions including the postpartum state,
immunologic 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 coagulation factor VII
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 VII ACTIVITY ASSAY
Adults: 65-180%
Normal, full-term newborn infants or healthy premature infants may have decreased levels (> or
=20%) which increase within the first postnatal week but may not reach adult levels for > or =180 days
postnatal.*
*See Pediatric Hemostasis References in Coagulation Studies in Special Instructions.
FACTOR VII 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
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