Alternative names, keywords |
APTT ratio, activated partial thromboplastin time ratio, INR, international normalized ratio, clotting screen, fibrinogen (Clauss). |
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Samples required |
Trisodium citrate blood (blue cap, 3.5 mL tube) taken with minimal stasis, filled to the line. Smaller tubes are available for paediatric samples. Samples must be analysed or processed in the laboratory within 4 hours of venepuncture. |
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Test indications |
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Reference range |
Source: locally determined. |
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Turnaround time |
1 working day (2 hours if identified as urgent). |
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Enquiries |
Haematology (Coagulation) |