Platelet Function Tests

Department of Haematology

Notes

These tests are only performed by appointment following discussion with the Consultant Haematologist. 

• Platelet function analysis (PFA) has replaced the Bleeding Time test. PFA includes collagen/EPI and collagen/ADP closure times.
• Platelet function tests by platelet aggregation includes platelet aggregation with ADP, EPI, Collagen, Ristocetin and Arachidonic acid. This test set also includes platelet nucleotide assay.
• PFA and platelet aggregation is performed at CGH and platelet nucleotide assay is performed at the Oxford Haemophilia Centre.
• Please note: these tests do not conform to CPA standard H5.4 as no external quality assurance scheme is available for all components. Therefore, these tests are not accredited by CPA.

Sample Requirements

DO NOT SEND THESE SAMPLES VIA THE AIR TUBE SYSTEM. Transporting samples via the air tube system may cause platelet activation and/or aggregation, leading to erroneous results. As such, samples transported via the air tube system will not be tested.

Platelet Function Tests

2 x 3ml or 3.5ml Trisodium Citrate samples

x 2

Platelet Nucleotide Assay

2 x 3ml or 3.5ml Trisodium Citrate samples

x2

Platelet Aggregation Studies

A minimum of 24ml blood is required for platelet aggregation studies:

8 x 3ml or 3,5ml Trisodium Citrate samples

x8

Turnaround Times

• PFA and Platelet aggregation: 1 day (by prior arrangement)
• Platelet nucleotides: 6 weeks

Sample Storage and Retention

• Pre analysis storage: do not store, send straight to laboratory. Please send by porter - do not use air tube.
• Sample retention by lab: Platelet function and aggregation studies require large volumes of blood, and as such there is rarely any blood remaining to retain. If there is sufficient blood, samples are retained for a minimum of 24 hours at  15-30°C. Samples sent for platelet nucleotides will be retained by Oxford Haemophilia Centre, as per their local guidelines.

These tests are by pre-arrangement only via the Consultant Haematologists, and cannot be requested as add-on tests.

Reference Ranges

Platelet aggregation studies with ADP, EPI, Collagen, Ristocetin and Arachidonic acid give qualitative results.

An interpretation of results will be available on computer system and printed on the final report form