Platelet Aggregation Test

General Information

A 'normal control' must be collected from a willing, consenting donor as soon as possible after collection of patient samples. All requests for Platelet Aggregation testing must be accompanied by a patient questionnaire (click Here). Please complete all information fully 

Samples that meet the following criteria will not be processed:

• Haemolysed, clotted, underfilled or overfilled samples.
• Samples >4 hours old from the time of collection.
• Samples which fail the minimum data set

Assay Limitations:

• Testing may not be appropriate in patients taking medications that can affect platelet function. These medications should be discontinued 7–10 days before testing if clinically appropriate. The pre-analytical questionnaire must be completed for all patients and the information taken into consideration when any aggregation anomalies are seen.
• Care should be taken when separating PRP and PPP; plasma should be carefully removed without disturbing the buffy coat layer or red cells. Red cells and white cells will interfere with the light transmission and cause reduced response amplitude, which can be mistaken for abnormal aggregation.
• Haemolysed samples are not suitable as this leads to activation or desensitisation of platelets. Light transmission will also be reduced due to the increase of released haemoglobin.
• Lipaemia impacts the baseline turbidity of the sample, and traces will be similar to those obtained in samples with low platelet counts. It may be possible to test the samples depending on the degree of lipaemia, but the final report should indicate that the sample was lipaemic.
• Aggregation should be performed within four hours of the blood being taken to reduce the chances of storage artefacts affecting platelet function.

For more information please see https://labtestsonline.org.uk/tests/platelet-function-tests