What is in a PRP treatment

Platelets carry messages that begin repair work

Platelets are tiny blood parts that gather when you get a cut. They release chemical messages telling nearby cells that repair work has started. Plasma is the liquid that carries these platelets in your blood.

Clinic staff put the blood tube in a centrifuge, which is a spinning machine. Heavy red cells settle below the plasma, platelets, and nearby white cells. The clinic's method tells the trained staff which layer to keep.

Leukocyte rich prp contains more white blood cells

Leukocyte is the medical name for a white blood cell. Leukocyte rich prp keeps more white cells, while the poor type leaves most behind. Neither name tells you which type fits your sore area.

Different machines and layers can produce different amounts of platelets. Concentrated PRP has platelets crowded into less liquid. Yet crowding alone doesn't tell you how many platelets are in the entire treatment.

A useful answer names the cells and the total amount

Ask whether the final PRP is checked for its total platelet amount. A useful reply gives the measured number or says the clinic doesn't measure it. A claim that it is very concentrated gives only part of the answer.

After treatment, follow the clinic's advice about movement and rest. Mild soreness and swelling can last a few days, but spreading redness or fever needs prompt care. A platelet number may describe the PRP, but it can't promise relief.

Sources

1. A systematic review that screened 876 studies and extracted standardised data from 33 commercially available PRP systems and protocols found that final product concentrations of platelets, white cells and growth factors varied widely between systems, as did the preparation protocols themselves. Platelet concentration correlated directly with the volume of blood drawn and with the centrifugal force of the device. The authors called the heterogeneity between separation systems something that 'must be resolved for proper study of this promising treatment'.

   Fadadu PP, Mazzola AJ, Hunter CW, et al. — Review of concentration yields in commercially available platelet-rich plasma (PRP) systems: a call for PRP standardization. Regional Anesthesia and Pain Medicine, 2019. DOI: 10.1136/rapm-2018-100356.

2. The PAW classification was proposed because PRP preparation protocols 'vary widely between authors and are often not well documented in the literature, making results difficult to compare or replicate'. It sorts preparations by three variables: the absolute number of Platelets, the manner of Activation, and the presence or absence of White cells - the three levers that make two injections both called 'PRP' materially different products.

   DeLong JM, Russell RP, Mazzocca AD — Platelet-rich plasma: the PAW classification system. Arthroscopy, 2012. DOI: 10.1016/j.arthro.2012.04.148.

3. Three healthy adults each donated 181 mL of blood which was processed through four commercial PRP kits (GPS III, Smart-Prep2, Magellan, ACP). The three kits that draw from the buffy-coat layer produced platelet concentrations 3-6 times baseline and white-cell concentrations 3-6 times baseline; the one kit drawing from plasma produced platelet concentrations only 1.5 times baseline. The authors concluded that the lack of standardisation of PRP preparation has contributed, at least in part, to the varying clinical efficacy reported for PRP.

   Fitzpatrick J, Bulsara MK, McCrory PR, et al. — Analysis of Platelet-Rich Plasma Extraction: Variations in Platelet and Blood Components Between 4 Common Commercial Kits. Orthopaedic Journal of Sports Medicine, 2017. DOI: 10.1177/2325967116675272.

4. In a controlled laboratory study, blood from five healthy donors was processed through three commercial PRP systems (MTF Cascade, Arteriocyte Magellan, Biomet GPS III). Platelet, red-cell and TGF-beta1 concentrations did not differ significantly between systems, but white-cell counts and PDGF-alpha-beta, PDGF-beta-beta and VEGF concentrations differed significantly across all three. Cascade produced leukocyte-poor PRP while GPS III and Magellan produced leukocyte-rich PRP with correspondingly higher white cells and growth factors.

   Castillo TN, Pouliot MA, Kim HJ, et al. — Comparison of growth factor and platelet concentration from commercial platelet-rich plasma separation systems. American Journal of Sports Medicine, 2011. DOI: 10.1177/0363546510387517.

5. A technical and biological review screened 1379 studies and identified 50 commercial PRP preparation systems in three technical categories (tubes, syringes, bags). Sufficient biological characterisation was available for only 14 of those 50 systems. Comparing the 36 characterised preparations across the seven existing PRP classifications revealed 'a large heterogeneity among the available current PRP commercial systems' and showed the classifications themselves differ in how well they discriminate between preparations.

   Magalon J, Brandin T, Francois P, et al. — Technical and biological review of authorized medical devices for platelets-rich plasma preparation in the field of regenerative medicine. Platelets, 2021. DOI: 10.1080/09537104.2020.1832653.

6. The DEPA classification was built because platelet and leukocyte counts alone do not describe an injection. Applied retrospectively to 20 published PRP preparations, the dose of injected platelets ranged from 0.21 billion to 5.43 billion - a 25-fold spread. No device recovered more than 90% of the platelets in the blood drawn, and most preparations were contaminated with red blood cells: only three of the devices reached a purity score corresponding to more than 90% platelets relative to red cells and leukocytes.

   Magalon J, Chateau AL, Bertrand B, et al. — DEPA classification: a proposal for standardising PRP use and a retrospective application of available devices. BMJ Open Sport & Exercise Medicine, 2016. DOI: 10.1136/bmjsem-2015-000060.