Newcastle Laboratories

Activated Partial Thromboplastin Time

Clinical Background:

This is the time it takes anticoagulated plasma to clot after being exposed to phospholipids, activators and calcium. It is used as part of the clotting screen and is sensitive to deficiencies in F...

This is the time it takes anticoagulated plasma to clot after being exposed to phospholipids, activators and calcium. It is used as part of the clotting screen and is sensitive to deficiencies in Factors XII, XI, IX, VII, X, V, II and Fibrinogen, in addition it may also detect deficiencies in the contact factors (High Molecular Weight Kininogen and Pre-Kallikrein). The test is also sensitive to Heparin (both Unfractionated and Low Molecular Weight) and the Lupus Anticoagulant. APTT can be increased by a number of the Direct Oral Anticoagulants which are being used more widely

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Test Details

  • Discipline:

    Haemostasis

    Haemostasis

  • Specimen Container Adult:

    Light blue - sodium citrate

    Light blue - sodium citrate

  • Specimen Container Paediatric:

    Light blue - sodium citrate

    Light blue - sodium citrate

  • Minimum Volume Adult:

    2.7mL

    2.7mL

  • Minimum Volume Paediatric:

    1.3mL

    1.3mL

  • Special Requirement:

    Tube must be correctly filled to line, to ensure correct ratio of blood to anticoagulant, ensure adequate mixing.

    Tube must be correctly filled to line, to ensure correct ratio of blood to anticoagulant, ensure adequate mixing.

  • Sample Stability:

    8 hrs

    8 hrs

  • Transport Requirements:

    Samples should be transported to lab without delay

    Samples should be transported to lab without delay

  • Freq Analysis:

    Continuous

    Continuous

  • Add On Test:

    All urgent add ons via telephone on 0191 28 24718, and must be confirmed via email to the appropriate email address

    RVIadditions.Laboratory@nuth.nhs.uk (internal)

    tnu-tr.bloodsciencesadditions@nhs....

    All urgent add ons via telephone on 0191 28 24718, and must be confirmed via email to the appropriate email address

    RVIadditions.Laboratory@nuth.nhs.uk (internal)

    tnu-tr.bloodsciencesadditions@nhs.net (external)

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  • Quality Assurance:

    UK NEQAS Blood Coagulation

    UK NEQAS Blood Coagulation

  • Reference Ranges:

    APTT 25 - 37 seconds

    APTT 25 - 37 seconds

  • Factors Affecting Result:

    Heparin will prolong the APTT

    Heparin will prolong the APTT

  • Other Info:

    As part of a coagulation screen.

    As part of a coagulation screen.

  • Routine Contact Name:

    Peter Strong

  • Routine Telephone:

    0191 282 0332

    0191 282 0332

  • Routine Email:

  • Specialist Test:

    No

    No

  • Specialist Contact Name:

    Haematology/Haemostasis Health care Scientist

    Haematology/Haemostasis Health care Scientist

  • Specialist Telephone:

    0191 213 9758

    0191 213 9758

Availability:

All times, both sites

Turn Around:

Urgent within 1 hour.

Routine within 4 hours.

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