A special blood concentrate known as platelet-rich plasma (PRP) can promote healing in a wide range of medical and surgical situations, but research has been limited by the lack of a universally accepted approach to measuring the platelet concentrations contained in PRP. A study in the September/October issue of The Journal of Craniofacial Surgery presents an accurate approach to measuring platelet counts in PRP preparations, using standard hematology equipment.
Jennifer E. Woodell-May, Ph.D., and colleagues at Biomet, Inc., of Warsaw, Ind., developed an approach to measuring platelet concentrations in PRP using a conventional automated hematology analyzer. The analyzer was capable of measuring platelet counts of up to 2 million platelets per microliter—relatively high, but below the very high counts contained in PRP preparations.
For the current study, platelet concentrations in PRP specimens were measured in two ways: using the authors' automated approach and a time-consuming manual count technique.
Comparisons showed no significant difference between the automated and manual counts: the average difference was only about one percent. The average amount of variation was significantly lower with the automated technique: about three percent, compared to seven percent with the manual count technique.
The automated counts were highly accurate, even though the platelet concentrations contained in the PRP preparations were beyond the limit of the hematology equipment in typical use. Platelet concentrations of over 3 million cells per microliter were accurately measured. Further studies suggested that accurate measurements could be made at platelet concentrations up to 4.8 million per microliter.
Platelet-rich plasma preparations, sometimes called "platelet gels," are made by taking a small sample of the patient's own blood and producing a specimen with a very high concentration of platelets. Platelets are blood cells that play a crucial role in blood clotting, and also carry certain blood factors that contribute to wound healing.
Studies have suggested that PRP preparations may promote healing in medical situations ranging from tennis elbow to spinal surgery. Platelet gels may be especially helpful in patients recovering from certain types of plastic and reconstructive surgery, improving healing while reducing the risk of complications. However, studies of PRP have yielded varying results, likely reflecting differing platelet concentrations.
The authors' technique, using conventional automated hematology equipment, provides an approach to assessing and standardizing the platelet concentrations contained in PRP preparations. "The ability to accurately measure platelet counts in PRP preparations is an important step forward in determining the true clinical value of these blood concentrates," comments Dr. Woodell-May. "We hope our platelet suspension technique and system validation method will aid in creating standardized PRP preparations with more predictable results, as well as in comparing the results of studies from different research groups."