Variation in Platelet Activation State in Pre-Donation Whole Blood: Effect of Time of Day and ABO Blood Group

Abstract

Background

Whilst there has been investigation into the effect of time of the day on platelet activation and function in healthy individuals, there is a lack of studies in the literature to examine this relationship among platelet donors.

Methods

We assessed the extent of platelet activation by percentage of platelets with surface-expressed P-selectin and flow cytometry in samples of whole blood from a group of qualified platelet donors (n = 84).

Results

The mean (SD) percentage of activated platelets in the pre-donation blood samples was 1.85 ± 1.57% (range 0.2–7.5%). In univariate analyses, the percentage of activated platelets was significantly and inversely correlated with the collection time (ie, the time of day blood samples were collected) (r = –0.35, p = 0.001) and positively correlated to mean platelet volume (MPV) (r = 0.29, p = 0.008). A weaker positive correlation was also observed with ABO blood group (r = 0.228, p = 0.036). Analysis of the collection time as a categorical variable showed a greater degree of activated platelets in samples collected between 8:00 h and 10:00 h than in samples collected during the hours of >10:00 h ≤14:00 h (2.5 ± 1.8 versus 1.1 ± 0.74, p < 0.001). In the adjusted linear regression model, collection time was a significant independent predictor of platelet activation state in whole blood (β = –0.26; p < 0.001), as did ABO blood group (β = 0.55; p = 0.019).

Conclusion

Our results show that collection time is the most important predictor of platelet activation state in pre-donation whole blood among platelet donors. This work may have implications for optimizing the timing of platelet donation.

Keywords:

• platelet activation state
• surface P-selectin
• donor variability

Abbreviations

MPV, mean platelet volume; PDW, platelet distribution width; P-LCR, platelet-large cell ratio; MCV, mean corpuscular volume; MCH, mean corpuscular hemoglobin; RDW, red blood cell distribution width; IPF, immature platelet fraction; IPC, immature platelet count.

Acknowledgments

We wish to thank the platelet donors for their participation in this study and the interviewing/apheresis staff at our Blood Bank for help with recruiting donors and preparation of the blood samples for flow cytometry analysis. We also thank the staff of the Hematology laboratory for measurement of platelet indices and the staff of the Department of Epigen at Akershus University Hospital for hematological analyses and flow cytometry access.

Disclosure

The authors declare no conflicts of interest in this work.

Additional information

Funding

This study received no funding.