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Activated partial thromboplastin time ratio (APTTR)

Category Haematology
Test background

The APTTR is derived from the activated partial thromboplastin time (APTT) of the patient and the midpoint of the APTT reference range. The APTTR is used to monitor unfractionated heparin therapy and is only reported under those circumstances.

Clinical Indications

Monitoring of unfractionated heparin dosage.

Reference range

Therapeutic range dependent on clinical requirement for anticoagulation.

Sample & container required 4.5 mL sodium citrate (pale blue top) adults1.8 mL sodium citrate (pale blue top) paediatrics
Turnaround time 4 hours

Special handling: avoid prolonged stasis during venepuncture. Sample must be received by lab within 4 hours of collection. Please note: samples will be rejected if underfilled or overfilled.