Factor XIII [CO002400]
Related Information
Synonyms Fibrin Stabilizing Factor; Fibrinoligase; Laki-Lorand
Factor
Abstract Activated factor XIII stabilizes fibrin clots by
cross-linking fibrin strands. Factor XIII deficiency can cause a
hereditary bleeding disorder with features including delayed bleeding,
umbilical stump bleeding, and miscarriages.
Specimen Plasma
Container One blue top (sodium citrate) tube
Collection Routine venipuncture. If multiple tests are being
drawn, draw blue top tubes after any red top tubes but before any
lavender top (EDTA), green top (heparin), or gray top (oxalate/fluoride)
tubes. Immediately invert tube gently at least 4 times to mix. Tubes
must be appropriately filled. Deliver tubes immediately to the laboratory.
Storage Instructions Separate plasma from cells as soon as
possible. Plasma may be stored on ice for up to 4 hours; otherwise,
store frozen.
Causes for Rejection Specimen received more than 4 hours
after collection, tubes not filled, clotted specimens
Turnaround Time Screening assay: 24 hours after incubation
begins; quantitative assay: several days (typically it is a send-out
test)
Reference Interval Screening assay: Clot stable in 5 M urea
for at least 24 hours. If factor XIII deficiency is present, clot
will usually dissolve in 1-2 hours. Quantitative assay: 70% to 140%
of normal (some newborns have lower levels than adults).1
Use Consider this test in patients with evidence for a familial
bleeding disorder and a normal PT, PTT, and von Willebrand panel
(because factor XIII deficiencies do not prolong the PT or PTT,
and von Willebrand disease is a much more common disorder than factor
XIII deficiency).
Factor XIII deficiency is rare. It causes delayed bleeding because
although fibrin clots can form initially, they are weak and subsequently
lyse. Factor XIII consists of two catalytic A subunits and two noncatalytic
B subunits. Most mutations causing factor XIII deficiency have so
far been found in the A subunit. The PT and PTT are normal in factor
XIII deficiency because factor XIII stabilizes the clot after a
fibrin clot has formed, whereas the PT and PTT measure the clotting
time through initial fibrin formation. Inheritance is autosomal.
Formerly, it was believed that heterozygotes are asymptomatic, but
more recent evidence suggests they can have bleeding symptoms.2
Symptoms include poor wound healing, umbilical stump bleeding, miscarriage,
prolonged bleeding from superficial wounds, and intracranial hemorrhage,
in addition to a number of other bleeding symptoms.
Limitations Screening assay: will not detect heterozygotes;
quantitative assay: expensive, not readily available, and high ammonia
levels may falsely decrease the result
Methodology A qualitative factor XIII assay evaluates clot
stability in 5 M urea. The patient sample is clotted by adding calcium,
and then after 30 minutes at 37degrees C the clot is placed in 5
M urea for 24 hours at room temperature. Clots formed by normal
individuals remain stable in 5 M urea, while clots from factor XIII
deficient patients dissolve in urea. This assay detects only the
most severely affected homozygous patients with 1% to 2% factor
XIII activity or less. A quantitative assay can detect heterozygous
deficiencies (with values of ~50%), but this test is not yet readily
available in most U.S. laboratories. In the quantitative assay,
factor XIII is activated by thrombin. Activated factor XIII then
attaches glycine ethyl ester to a specific peptide substrate, releasing
ammonia. The released ammonia generates a subsequent reaction that
is detected by a photometer.
Additional Information When fibrin initially forms, fibrin
monomers are held together by weak noncovalent hydrogen bonds. Factor
XIII is a transglutaminase that stabilizes fibrin clot by cross-linking
fibrin monomers with covalent bonds. Calcium is required for its
activation by thrombin as well as its activity. It also cross-links
antiplasmin to fibrin, which protects the clot from fibrinolysis
by plasmin.
A factor XIII polymorphism (Val34Leu), present in nearly half of
the population, is suspected to protect against deep venous thrombosis
and is somewhat more frequent in patients with intracranial hemorrhage.3,4
Factor XIII has a long half-life of 10-12 days. Therefore, treatment
of factor XIII deficiency can be successful with infrequent doses
of cryoprecipitate, fresh frozen plasma, or if available, factor
XIII concentrates. Acquired decreases in factor XIII can arise in
liver disease (decreased hepatic synthesis), disseminated intravascular
coagulation (DIC), certain inflammatory diseases (Crohn, ulcerative
colitis, Henoch-Schönlein purpura), leukemia, myelodysplasia,
and myeloproliferative disorders. Over 25 cases of inhibitors (antibodies)
against factor XIII have been reported.5,6
Footnotes
1. Andrew M, Paes B, and Johnston M, "Development of the Hemostatic
System in the Neonate and Young Infant,"Am J Pediatr Hematol
Oncol, 1990,12(1):95-104.
2. Seitz R, Duckert F, Lopaciuk S, et al, "ETRO Working Party on
Factor XIII Questionnaire on Congenital Factor XIII Deficiency in
Europe: Status and Perspectives,"Semin Thromb Hemost, 1996,
22(5):415-8.
3. Catto AJ, Kohler HP, Coore J, et al, "Association of a Common
Polymorphism in the Factor XIII Gene With Venous Thrombosis,"Blood,
1999; 93(3):906-8.
4. Catto AJ, Kohler HP, Bannan S, et al, "Factor XIII Val 34 Leu:
A Novel Association With Primary Intracerebral Hemorrhage,"Stroke,
1998, 29(4):813-6.
5. Standen G, Birchall J, Morse C, et al, "A Large Bruise,"Lancet,
1999, 353(9168):1934.
6. Lorand L, Velasco PT, Murthy P, et al, "Autoimmune Antibody
in a Hemorrhagic Patient Interacts With Thrombin-Activated Factor
XIII in a Unique Manner,"Blood, 1999, 93(3):909-17.
References
Egbring R, Kroniger A, and Seitz R, "Factor XIII Deficiency: Pathogenic
Mechanisms and Clinical Significance,"Semin Thromb Hemost,
1996, 22(5):419-25.
Mikkola H and Palotie A, "Gene Defects in Congenital Factor XIII
Deficiency,"Semin Thromb Hemost, 1996, 22(5):393-8.
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