Educational guide
Single spin vs double spin PRP
A single spin separates whole blood once and you draw off the plasma above the red cell layer. A double spin adds a second run that pellets the platelets, lets you remove the platelet-poor plasma, and resuspends the pellet in a smaller volume. Double spin raises concentration; single spin is faster and uses fewer handling steps.
Figures below are general PRP-class literature or manufacturer-reported device specifications. They describe preparation methods and device output, not the clinical results of any preparation.
What actually happens in a single spin?
One run in the centrifuge sorts whole blood by density, and you aspirate the platelet-containing plasma sitting above the packed red cells. There is no second concentration step, so the platelets stay distributed through whatever plasma volume you draw.
Emcyte's instructions for the single-spin AbsolutePRP Pure Gold kit describe exactly that sequence: load 20 mL of anticoagulated whole blood, counterbalance, spin once, then aspirate the platelet-rich plasma separated above the RBC layer, leaving the red cells behind. Load, spin, draw.
Because the plasma is never reduced, the final concentration is capped by how much plasma you take up with the platelets. Draw a smaller volume and you leave platelets in the device; draw a larger volume and you dilute what you captured.
What does the second spin add?
The second spin turns a separation step into a concentration step by pelleting the platelets so the excess plasma can be removed. The Emcyte PurePRP SP instructions (June 2024) walk through it on the 60 mL kit: after the first spin the platelet-plasma suspension is reinjected into the device; after the second spin the platelet buffy coat is separated at the bottom, you draw off plasma leaving 7 mL, swirl to resuspend, and extract 7 mL of PRP.
The plasma you remove between those steps is the platelet-poor plasma. Taking it out shrinks the denominator. Same platelets, less plasma, higher concentration.
How much more concentrated is double-spin PRP?
In published comparisons, double-spin preparations land roughly 1.4 to 1.6 times higher in platelet concentration than single-spin preparations from the same donors. The figures below are general PRP-class literature. They describe preparation methods in a lab, not the output of any device sold on this page, and they are not statements about clinical results.
| Measure | Single spin | Double spin | Source |
|---|---|---|---|
| PRP platelet count, 50 healthy donors | 594.6 ± 157.4 ×10³/µL | 923.06 ± 127.58 ×10³/µL | Saqlain 2023 (p < 0.01) |
| Concentration vs same donor's whole blood | 175.75 ± 55.08% | 276.78 ± 112.7% | Saqlain 2023 (p < 0.01) |
| Residual white blood cells | 6.06 ×10³/µL | 1.06 ×10³/µL | Saqlain 2023 (p < 0.01) |
| Residual red blood cells | 0.0588 ×10⁶/µL | 0.0436 ×10⁶/µL | Saqlain 2023 (p = 0.139, n.s.) |
| Platelet enrichment, knee OA trial (14/arm) | 2.33x baseline | 3.18x baseline | Adv Rheumatol 2026 |
| Platelet capture yield, six single-spin methods | 53% to 72% | not measured | Harrison 2020 |
Sources: Saqlain N, et al. Pak J Med Sci. 2023;39(3):634-637 (PMID 37250535). Adv Rheumatol. 2026;66:15 (platelet-enrichment figures only). Harrison TE, et al. Platelets. 2020;31(5):661-666 (PMID 31498027). General PRP-class literature, not device data.
What does the second spin cost in chair time and handling?
About four and a half extra minutes of spin time plus three extra bench steps. Every figure below is manufacturer-reported from the instructions for use, timed on the Executive Series centrifuge.
| Workflow step | AbsolutePRP Pure Gold | PurePRP SP | Pure Two PRP |
|---|---|---|---|
| Spins | 1 | 2 | 2 |
| Total time in the centrifuge | 1.5 min | 6.0 min | 6.0 min |
| Disposables per case | 1 concentrating device | 1 integrated device | 2 (separator + concentrator) |
| Counterbalance operations | 1 | 1 | 2 |
| Transfer step between spins | None | Yes, same device | Yes, into 2nd device |
| Platelet-poor plasma drawn off | No | Yes | Yes |
| Final PRP volume | not specified in public IFU | 7 mL | approximately 7 mL |
Manufacturer-reported, from the Emcyte instructions for use (AbsolutePRP Gold; PurePRP SupraPhysiologic Concentrating System, June 2024; PurePRP Two). Spin times are for the Executive Series; Sapphire and Platinum series run named presets. Device workflow specifications, not clinical-performance claims.
Two things fall out of that. The extra chair time is real but small, and it is spin time that runs unattended. The handling cost is what practices underestimate: a transfer, a plasma draw-off, and a resuspension are three more chances to vary technique between operators.
Does higher concentration always mean a better result?
No, and the literature is not settled. Concentration is a specification of the preparation; it does not translate one-to-one into a clinical result. A 2025 systematic review of three randomized trials (90 patients) in androgenetic alopecia found no statistically significant difference in platelet concentration between single-spin and double-spin arms as pooled (mean difference 66.14, 95% CI −372.96 to 505.25, p = 0.77; high heterogeneity, I² = 83.5%). That is general background literature, not a statement about any device on this page, and PRP Direct makes no claim that any preparation treats any condition.
The practical reading: pick the spin protocol that fits the case and the workflow your team can run consistently, and document what you actually produced.
Which kits are single spin and which are double spin?
One kit in the line is single spin; the rest of the PRP family is double spin. All run on the same Sapphire centrifuge, so a practice can carry both without a second machine.
| Manufacturer-reported spec | AbsolutePRP Pure Gold | PurePRP SP | Pure Two PRP |
|---|---|---|---|
| Spin | Single | Double | Double |
| Platelet yield (capture) | not published | ≥ ~90% | not published separately |
| Concentration vs baseline | not published | ≥ 6x | not published separately |
| Hematocrit in final PRP | not published | < 1% | not published separately |
| PRP volume | not published | 7 mL | approximately 7 mL |
| Neutrophil-rich or -poor selectable | not published | Yes | Yes, protocol A or B |
| Kit sizes | 20 mL | 30 / 60 / 120 mL | 30 / 60 / 120 mL |
| Regulatory status | 510(k)-cleared blood-processing devices | ||
Manufacturer-reported, from the Emcyte product pages and kit instructions for use. Cells marked "not published" are left blank because the manufacturer does not publish that figure for that kit. Yield and concentration figures describe what the device produces in the tube, not the clinical efficacy of the prepared biologic.
PurePRP SP or Pure Two PRP: the actual difference
Both are double spin, and Emcyte's instructions give them the same spin protocol and the same final volume, so platelet counts are comparable. The difference is the disposable and the bench workflow. On the 60 mL kits both run 2.0 then 4.0 minutes at 4400 RPM and finish at 7 mL. PurePRP SP does both spins inside one integrated disposable, counterbalanced once. Pure Two PRP splits the job across a separator and a concentrator device, with two separate balance steps.
The argument for SP is that fewer transfers mean less platelet-to-plastic contact across the process, a rationale based on how the workflow is built, not a published head-to-head recovery comparison. The simpler SP argument needs no interpretation: one disposable to stock and one counterbalance to get right instead of two. Pure Two PRP remains widely used, and for a team already standardized on the two-step protocol, staying put is reasonable.
Which one fits your practice?
- Starting a PRP service, or short appointment slots. The single-spin AbsolutePRP Pure Gold 20 mL kit is the lowest-friction entry: one load, one counterbalance, one aspiration, in about two minutes, at a lower concentration.
- Highest dose per case with the simplest double-spin bench. PurePRP SP, one integrated disposable, counterbalanced once, in 30, 60, or 120 mL.
- Team already trained on the two-device protocol. Pure Two PRP, comparable counts on the workflow you already run.
- You want to document the dose rather than assume it. Pair any of them with a chairside analyzer and record the baseline against the finished preparation.
Not sure which spin protocol to stock?
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Request a quotePRP Direct distributes 510(k)-cleared autologous blood-processing devices. Clearance covers how the device processes blood; it is not a clearance of the prepared PRP to treat any condition, and no PRP therapy is FDA-approved for a specific indication. Manufacturer specifications are not claims of clinical efficacy. This page is general education and is not medical advice.