PURPOSE: The purpose of this study is to describe the inter- and intra-individual differences in the platelet concentration between blood and platelet-rich plasma (PRP) preparation, assess intersubject differences considering demographic and anthropometric variables, describe PRP code distribution and analyse intrasubject variability. METHODS: A retrospective analysis was conducted using a single-centre patient database from November 2021 to November 2023. It included patients with musculoskeletal pathologies treated with PRP injections. Primary variables were demographic characteristics (sex, age, body mass index [BMI]) and platelet concentrations in blood and PRP during treatments. Secondary analysis focused on PRP code frequency distribution and intrasubject variability according to different coding systems. RESULTS: Here, 686 patients met the inclusion criteria. PRP exhibited significantly higher platelet concentrations compared to blood (378.01 ± 136.25 × 10 CONCLUSION: Age, gender, BMI and intrasubject variations significantly affect PRP formulation, emphasizing the importance of addressing these variables for a more predictable, personalized and effective therapeutic approach. LEVEL OF EVIDENCE: This is a retrospective study. Level IV.