Laboratory Medicine

Test Directory / Coagulation factor XII assay

Coagulation factor XII assay

Citrated Plasma

Test	Coagulation factor XII assay
Common Abbreviations	FXII
Profile	Coagulation Screen added on the same sample
Clinical Indication	To determine if the coagulation factor XII is low or absent. Associated with reduced clot formation and bleeding. Contact Consultant Haematologist for advice.
Specimen Type	Blood
Sample Type	Citrated Plasma
Minimum Volume	2 x 3 mL (adult) 2 x 1 mL (paed) (citrated plasma must be filled to bottle line)
Special Precautions	Must state if patient is on anticoagulants (DOAC, Warfarin, Heparin); known coagulation disorders; clincal symptoms (bleeding, bruising).
Stability	4-6 hours
Turnaround Time	4 hours (urgent) if requested via the haematology consultants. 3 weeks (routine)
Laboratory	York Hospital
Reference Interval	Reference range printed on final report.
Limitations	Haemolysis, gross lipaemia, high haematocrit may interfere with measurement. Over or under filled samples cannot be used due to ratio between blood and citrate
Additional Information

Update for visitors

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The following wards are closed to visitors:

York Hospital: Ward 29 and Ward 37.

There are four exceptions only to the restrictions. These are:

For patients who are receiving end of life care

Paediatric patients (babies and children)

Maternity care

The family carers of those with dementia

We understand these restrictions can be difficult when a loved one is unwell. The restrictions will be reviewed daily and lifted as soon as it is safe. Thank you for your understanding as we try to reduce the spread of norovirus in our hospitals.