Antithrombin III is ordered as part of a thrombophilia profile but can be ordered by Haematology independently for asparaginase therapy monitoring (below).

Clinical Relevance: Thrombosis is a well-recognized complication of asparaginase therapy for acute lymphoblastic leukemia (ALL), associated with the depletion of antithrombin (AT).
Reference Range: Current laboratory (adult, M/F) normal ranges are as follows:
80 – 129%
Min. Volume: The volume of blood in coagulation samples must lie within the volume range as indicated by the size of the black fill arrow present on tubes. Volumes above or below the arrow will result in sample rejection to ensure validity of results.
Turnaround Time: Therapy monitoring: 4 hours
Age of Sample: Samples will be rejected if received more than 1 hour post venepuncture.
Specimen Requirements:
  • 1 blue top (sodium citrate) sample.
  • All coagulation tubes must be adequately filled (see above).
  • All coagulation tubes must be mixed several times by gentle inversion immediately after venepuncture. Mixing the sample with the anticoagulant stops the sample clotting within the tube.
Limitations:
  • It is not possible to provide results on clotted, insufficient, lipaeamic, or haemolysed samples. These will be rejected with the appropriate comment.
  • Sample tubes that have expired cannot be accepted.
Analysing Laboratory: Coagulation (JCUH)
Referral Laboratory: Should samples require further testing they will be referred to:
Specialist Haematology Laboratory in Sheffield and Sheffield Molecular Genetics