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Miscellaneous diagnostic tests in the haemostasis laboratories



  • Anti-Xa for LMWH monitoring
  • alpha 2 antiplasmin activity
  • TAT
  • Prothrombin fragment 1:2
  • Factor XIII
  • Fibrinogen Ag
  • TAFI antigen


All results are available within two weeks although anti-Xa estimations can be performed urgently.

External users may contact the laboratory for information related to result progress.


Requests for these assays and urgent anti-Xa levels must be discussed with a consultant of the Centre for Haemostasis and Thrombosis.

Sample requirements

Citrate (blue top tube)

Anti-Xa samples must be taken to the laboratory on ice, please contact laboratory for details of phlebotomy and delivery. Each test requires one 4.5ml citrated sample.

FXIII requests also require a special Lithium Heparin tube from Clinical Biochemistry for an ammonia level to be performed.


Please call 020 7188 2797, Monday to Friday, 9am-5.15pm.