What is the difference between single spin Platelet-Rich Plasma (PRP) and double spin PRP in terms of clinical applications?

Single Spin vs Double Spin PRP: Key Differences and Clinical Implications

Double-spin PRP preparation yields higher platelet concentrations and better clinical outcomes compared to single-spin methods, making it the preferred technique for regenerative medicine applications.

Preparation Methodology

Single-Spin PRP

• Single-spin PRP uses one low-force centrifugation step (170-200g for 10 minutes at room temperature) to separate platelet-rich plasma from whole blood 1
• This method is simpler and faster but produces lower platelet concentrations 2
• Results in a relatively pure preparation with good yield, though platelet enrichment is limited 1

Double-Spin PRP

• Double-spin PRP involves two sequential centrifugation steps: an initial low G-force (soft) spin to produce platelet-rich plasma, followed by a higher G-force (hard) spin to concentrate platelets further 1
• The first spin separates PRP from red cells, while the second spin removes most platelet-poor plasma, concentrating the platelets 1
• This technique achieves mean platelet concentration ratios of 3.47-fold (range 2.48-5.71) compared to baseline whole blood 3
• The double-spin method can be performed in a closed system without opening the container, maintaining sterility 3

Clinical Efficacy Differences

Superior Outcomes with Double-Spin

• In female pattern hair loss treatment, double-spin PRP produced significantly higher terminal hair density compared to single-spin PRP when directly compared in the same patients 2
• Double-spin preparations yield higher concentrations of platelets and growth factors, which correlates with improved clinical outcomes 2
• The baseline whole blood platelet count positively correlates with final PRP platelet count (correlation coefficient 0.56), meaning higher starting counts yield better concentrated products 3

Cellular Composition Differences

• Double-spin PRP is enriched for lymphocytes and monocytes but contains significantly lower counts of neutrophils and eosinophils compared to baseline blood 3
• The presence of leukocytes may impact biology through immune and antibacterial properties, as well as tissue healing and local growth factor regulation 1
• Single-spin methods typically retain more white blood cells (10^8 to 10^9 WBCs per unit) 1

Practical Considerations

Standardization Requirements

• The field of regenerative PRP therapy suffers from poor standardization, with wide variability in preparation methods directly affecting clinical efficacy 1
• Differences in g-force and centrifugation time result in significant variations in yield, concentration, purity, viability, and activation status of isolated platelets 1
• Expert consensus strongly recommends standardization of PRP preparation methods, indication criteria, and application protocols 4

Processing Guidelines

• Blood should be collected in plastic tubes using trisodium citrate, ACD, or CPD anticoagulants (never EDTA, which causes platelet swelling and activation) 1, 5
• Process blood at room temperature as soon as possible, preferably within 1 hour of collection 5
• Freshly prepared PRP should be used within 4 hours for optimal results 5

Clinical Application Context

When to Choose Double-Spin

• For conditions requiring higher platelet concentrations and growth factor delivery, such as chronic tendinopathies, early knee osteoarthritis (Kellgren-Lawrence grade II), and hair loss, double-spin preparation is preferable 4, 2
• Multiple injections (2-4 sessions) are recommended for chronic lesions, though optimal time intervals between injections remain undefined 4

Activation Considerations

• Interestingly, VEGF concentration does not differ significantly between single- and double-spin prepared PRP, nor does it increase with calcium activation 2
• This suggests that the superior clinical outcomes with double-spin PRP relate to overall platelet concentration rather than individual growth factor levels 2
• Activation protocols should include calcium chloride, autologous thrombin, or collagen type I, depending on the clinical application 5

Common Pitfalls to Avoid

• Do not use EDTA as an anticoagulant, as it causes premature platelet activation 1, 5
• Avoid storing PRP at 4°C, as cold activation may occur prematurely 5
• Do not assume that adding calcium gluconate prior to injection provides additional benefit, as evidence shows no significant increase in growth factor concentration 2
• Ensure proper documentation of the specific preparation method used, as this significantly impacts reproducibility and clinical outcomes 1