Related Experiment Video
Updated: Aug 9, 2026
Preparation, Procedures and Evaluation of Platelet-Rich Plasma Injection in the Treatment of Knee Osteoarthritis
Published on: January 4, 2019
Reevaluation of the resting time period when preparing whole blood-derived platelet concentrates with the
Gary Moroff1, Linda Kline, Michelle Dabay
1American Red Cross, Jerome Holland Laboratory for the Biomedical Sciences, Rockville, MD 20855, USA. Moroff@usa.redcross.org
Background:
The resting of platelet (PLT) pellets during the preparation of whole blood-derived PLT concentrates (PCs) is considered an essential step. A reevaluation of the rest period was conducted because preparation and storage conditions have been modified during the past 20 years.
Study Design And Methods:
A two-site in vitro study (Study 1) was conducted with rest times of 0 to 5 minutes, 1 hour, and 4 hours (n = 31-33 per rest period). Leukoreduced PCs were stored for 5 days. A second study (Study 2) measuring in vivo viability was conducted at a third site (14 paired studies). PCs were prepared from 2 units of whole blood on the same day to simultaneously compare viability following storage and radioisotopic labeling.
Results:
In Study 1, comparable in vitro parameters and swirling were observed with the three rest periods. The mean (+/-1 SD) values after storage for the extent of shape change and hypotonic stress parameters were 0 to 5 minutes, 16.7 +/- 7.2 and 66.0 +/- 15.7%; 1 hour, 19.1 +/- 6.9 and 69.3 +/- 17.9%; and 4 hours, 17.6 +/- 5.5 and 64.1 +/- 11.3%. In Study 2, the in vivo recovery was 49.9 +/- 15.3 and 50.9 +/- 20.2% with 0- to 5-minute and 1-hour rest periods, respectively. The corresponding survival time was 111.2 +/- 50.7 and 114.9 +/- 43.8 hours.
Conclusion:
These studies indicate comparable in vitro and in vivo viability properties with 0- to 5-minute and 1-hour rest periods and at 4 hours (in vitro only).
