Factor XIII ( FXIII )

Coagulation

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Description

FXIII is the zymogen of a transglutaminase which is activated by thrombin in the presence of calcium and fibrin, it’s active form (FXIIIa). FXIIIa enables fibrin to covalently cross-link to form a stable fibrin clot. FXIII circulates as two catalytic A subunits and two non-catalytic B subunits.

The Berichrom FXIII activity assay is used at Sheffield. FXIII in plasma is activated to FXIIIa This then cross-links a specific peptide substrate to glycine ethyl ester which releases ammonia. The amount of ammonia released is determined in a partial enzymatic reaction involving NADH and α-ketoglutarate. The consumption of NADH is proportional to the level of FXIII in the plasma.

The Werfen FXIII antigen assay comprises latex particles coated with rabbit polyclonal antibodies to the A-subunit of the FXIII molecule. Measurement of FXIII antigen is by decrease in the amount of transmitted light of the latex particles when they bind to the A-subunit of FXIII.

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Indications

Reduced FXIII levels may occur in congenital FXIII deficiency, as an acquired deficiency or through unregulated activation of coagulation as in a consumption coagulopathy.

Congenital FXIII deficiency is a rare bleeding disorder commonly linked to poor wound healing. Early indicators of congenital FXIII deficiency include umbilical stump bleeding and prolonged bleeding post circumcision.

Current UK guidelines recommend testing of FXIII antigen in patients with reduced FXIII activity.

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Sample Type

0.5ml of platelet poor plasma.

A fibrinogen result is required on the same venepuncture before FXIII activity can be measured. This can be provided by the requesting laboratory or performed by our laboratory.

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Reference Range

Reference range is indicated on report.

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Turnaround Time

Within 10 days (or on demand)

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Testing Frequency

As required.

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External Notes

The accuracy of all coagulation tests is greatly influenced by pre analytical variables. It is essential that sample quality is given the highest of priorities. Samples which fail to meet quality criteria including age of sample, specimen fill (>90%), haemolysed, clotted or activated samples will be rejected and a repeat sample requested.

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References

Kohler et al (2011). Diagnosis and classification of FXIII deficiencies. J Thromb Haemost. 9;1404-1406.
Mumford et al (2014). Guideline for the diagnosis and management of the rare coagulation disorders. Br J Haematol. 167; 304-326.

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.