International Normalised Ratio (Blood)

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Testing Laboratory

Auckland Te Toka Tumai | Auckland Hospital

Department

Haematology

Delphic Registration Code (Alpha Code)

W

Test Code (Numeric Code)

1731

Laboratory Handling

Phlebotomy

  • Collect 1 x 2.7ml Citrate (Blue Cap) or 1 x 1.8ml Citrate (Light Blue Cap).
  • Paediatrics collect 1 x 1ml Micro-Citrate tube.
  • Tube must be adequately filled.
  • Whole blood International Normalised Ratio (INR) is available for paediatric patients for warfarin monitoring only. Please arrange this with phlebotomy (ext 29269) if this service is required.

    Transport

    Send the white form for the Whole Blood INR after numbering and registration directly to Coagulation.

    Registration

  • Whole Blood INR (Bedside INR) Delphic Test Code: WINR
  • INR + APTT( Patient on Heparin or Warfarin) Delphic Test Code: HS3
  • INR + APTT + FIB Delphic Test Code: HSF
  • Clinical Trials only: NINR

    Sample Stability

    INR is mathematically derived from Prothrombin Time expressed as a Prothrombin Ratio. It does not have independent sample stability and follows the same stability limits as the Prothrombin Ratio.

    Ambient (8 - 24°C) 24-hours
    -20°C 2-weeks

    • Synonyms

    INR

    Turnaround Time

    2 hours

    Specimen Type

    • Whole Blood

    Specimen Requirements

    Tube/Container Type:

    Preferred
    • Citrate (Blue Cap)
    Acceptable
    • Please refer to Additional Information below
    • Citrate (Light Blue Cap)
    Preferred Sample Volume (ml)

    2.7

    Minimum Sample Volume (ml)

    2.7

    No of Samples Required

    1

    Paediatric Specimen Requirements

    Tube/Container Type:

    Preferred
    • Citrate (Microtainer)
    Preferred Sample Volume (ml)

    1

    Minimum Sample Volume (ml)

    1

    Additional Specimen Information

    Collect 1 x 2.7ml Citrate (Blue Cap) or 1 x 1.8ml Citrate (Light Blue Cap).
    Tube must be adequately filled.
    Whole blood International Normalised Ratio (INR) is available for paediatric patients for warfarin monitoring only. Please arrange this with phlebotomy (ext 29269) if this service is required.

    Last updated: 26/08/2026