Haematology

Preferred Sample Type

PT / INR and Partial Thromboplastin Time (PTT)

PT / INR and Partial Thromboplastin Time (PTT)

Specimen Volume

3.5 mL

Specimen Transport

Standard transport to laboratory

Sample Preparation

Samples for any coagulation tests must be filled to the black fill line indicated on the sample tube. Any sample filled above or below this level will be rejected and a repeat sample will be required

Turnaround Time

24 hours

Sample Processing In Laboratory

Sample should be centrifuged

Sample Stability

12 hours from venepuncture (ideally received no later than 4 hours after collection)

General Information

Samples that meet the following criteria will not be processed:

  • Haemolysed, clotted, underfilled or overfilled samples.
  • Samples >12 hours old from the time of collection.
  • Samples received from other hospital laboratories that have been frozen and thawed.
  • Samples which fail the minimum data set.

Assay Limitations:

  • PT/INR: results are not affected by heparin up to 1 U/ml, haemoglobin up to 500 mg/dl, triglycerides up to 1000 mg/dl or bilirubin up to 30 mg/dl.
  • APTT: results are not affected haemoglobin up to 500 mg/dl, triglycerides up to 1000 mg/dl or bilirubin up to 26 mg/dl.
  • For grossly lipaemic samples an alternative mechanical clot detection based assay is used for PT and APTT

Notes

UFH Monitoring: Any patient whose APTT is being considered for UFH monitoring should have a baseline APTT performed prior to commencement of UFH therapy. If the pre-treatment APTT is prolonged or shortened, then the APTT is unsuitable for monitoring UFH therapy for that patient. In these cases, a heparin anti-FXa assay is a better option to monitor drug response.

Note samples for UFH monitoring by APTT require processing within 1 hour so MUST be sent via the urgent pathway.

Reference Range

Prothrombin Time ratio (PT) 0.8-1.2 (10-14.0 seconds)

INR Dependent upon therapeutic requirement

PTT Ratio 0.8-1.2 (23-34 seconds)

 

 

Specifications

  • EQA Status: NEQAS
  • EQAS Scheme: Yes

Tags

APTT PT PTT

Creation Date

Monday, 08 August 2011

Modification Date

Thursday, 28 November 2024

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Protection of Personal Information – Clinical Laboratory Services comply with the Trust Data Protection Policy and have procedures in place to allow the Directorate and it’s employees to comply with the Data Protection Act 1998 and associated best practice and guidance.

University Hospitals Birmingham medical laboratories at Queen Elizabeth Hospital, Heartlands Hospital, Good Hope Hospital and Solihull Hospital are UKAS (United Kingdom Accreditation Service) accredited to the ISO 15189:2012 standard. For a list of accredited tests and other information please visit the UKAS website using the following link: https://www.ukas.com/find-an-organisation/

  • Molecular Pathology is a UKAS accredited medical laboratory No. 8759
  • Biochemistry is a UKAS accredited medical laboratory No. 8910
  • Haematology and Transfusion is a UKAS accredited medical laboratory No. 8784
  • Clinical Microbiology is a UKAS accredited medical laboratory No. 8760
  • Cellular Pathology is a UKAS accredited medical laboratory No. 10141
  • Musculoskeletal laboratory is a UKAS accredited medical laboratory No. 9897
  • Heartlands, Good Hope and Solihull Hospital pathology laboratories are a UKAS accredited medical laboratory No.8217.

Tests not appearing on the UKAS Schedule of Accreditation currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further test information, please visit the test database: http://qehbpathology.uk/test-database

For further information contact Louise Fallon, Quality Manager, 0121 371 5962