Sorted By Test Name - Mayo Medical Laboratories

F7IS
7809
F8A
9070
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
Coagulation Factor VIII Activity Assay, Plasma
Clinical Information: Factor VIII is synthesized in the liver, and perhaps in other tissues. It is a
coagulation cofactor which circulates bound to von Willebrand factor and is part of the intrinsic
coagulation pathway. The biological half-life is 9 to 18 hours (average is 12 hours). Congenital factor VIII
decrease is the cause of hemophilia A which has an incidence of 1 in 10,000 and is inherited in a recessive
sex-linked manner on the X chromosome. Severe deficiency (