Condition category
Haematological Disorders
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
When people donate their blood platelets, they lose about 50% of them. Although this is perfectly safe, it is not clear how quickly their platelet count returns to normal and what causes this to happen: it’s possible that new platelets come from a “reserve pool” in the spleen and/or they are made by bone marrow. It is also not known what chemicals (growth factors) in the blood stream are important in making sure the number of platelets return to normal after donation. Knowing what these “platelet” growth factors are would be extremely useful for the treatment of patients with low platelet counts or in making platelets in the laboratory for transfusion. This study will compare how quickly the number of platelets return to normal and what growth factors are present in regular donors verses people who are about to donate for the first time.

Who can participate?
Adult male platelet donors who regularly donate at the Cambridge Blood Centre and those that are due to donate for the first time.

What does the study involve?
A blood sample is taken from each participant 30 minutes before the platelet donation begins, in the opposite arm to which the donation is taken from. Another sample is taken 10 minutes after the donation is complete, one 4-8 hours after donation and then a number of additional samples on days 1,3,7 and 14 after the donation are taken. Donors are given the choice whether they would like the bloods to be done at home, place of work or at the Blood Centre.

What are the possible benefits and risks of participating?
There are no significant benefits or risks to taking part in this study. Donations will take around 40 minutes longer than a normal platelet donation. The blood sampling may cause some mild discomfort and sometimes a small bruise.

When is the study starting and how long is it expected to run for?
September 2014 to September 2015.

Who is funding the study?
NHS Blood and Transplant Trust Fund (UK)

Who is the main contact?
Cedric Ghevaert

Trial website

Contact information



Primary contact

Dr Cedric Ghevaert


Contact details

NHS Blood and Transplant
Cambridge Blood Centre
Long Road
United Kingdom
+44 (0) 1223 588904

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Reticulated platelet release and mass spectrometry analysis of plasma proteins after apheresis platelet donation by established and new donors


Study hypothesis

Platelet donors donate their platelets through a process called apheresis. The donors have a cannula inserted into a vein and this blood line goes into a machine that spins the blood from the donor so as to separate it into different constituents (plasma, red cells, platelets). The red cells and plasma are given back to the donors, whilst the platelets are collected into a bag that can be transfused to a patient. The donation process takes about 1.5 hours. Platelet donors lose about 50% of their platelets, which gradually recover over 2 weeks with the formation of new platelets in the donor’s bone marrow. We hypothesize that this is driven by growth factors (in addition to thrombopoietin). We seek to identify the exact dynamics of platelet recovery following platelet donation and correlate it to the presence of plasma-bound growth factors through mass spectrometry

Ethics approval

NRES Committee East of England – Cambridge South, 22/05/2014, ref: 14/EE/0194

Study design

1-year laboratory study

Primary study design


Secondary study design


Trial setting


Trial type


Patient information sheet

The donors will be sent out a donor information leaflet, there will also be posters up in the blood centre advertising for donors


Platelet recovery following donation


The donors will have bloods taken pre and post donation and at another four timepoints over the next 2 weeks

Intervention type



Not Applicable

Drug names

Primary outcome measures

The primary objective of this study will be the accurate measurement of the platelet count, the platelet volume and the quantity of newly formed platelets in platelet apheresis donors at the time of donation and at early (4-8 hours) and late (day 1, 3, 7 and 14) time points after donation. From the same blood sample used to look at the platelet count, we will isolate the plasma and analyse it by mass spectrometry to identify which proteins contained in the blood promote new platelets release from the bone marrow.

Secondary outcome measures

Platelet donors give a donation every 4 weeks. Samples will be taken from established platelet donors and from newly recruited donors to establish whether the platelet count recovery and plasma proteins are different when platelet donations are done frequently.

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

Male platelet donors aged over 18 who are able to donate on Monday or Tuesday morning

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Female donors
2. HPA-1a-5b negative donors who are used to maintain the supply of platelets for treatment of neonatal alloimmune thrombocytopenia

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

NHS Blood and Transplant
United Kingdom

Sponsor information


NHS Blood and Transplant Trust Fund (UK)

Sponsor details

Oak House
Reeds Crescent
WD24 4QN
United Kingdom
+44 (0) 1923 366800

Sponsor type

Hospital/treatment centre



Funder type

Hospital/treatment centre

Funder name

NHS Blood and Transplant Trust Fund (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes