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Professional article · PRP cell profile & evidence
Leukocyte-rich or leukocyte-poor PRP?How to classify LR-PRP and LP-PRP correctly
Is leukocyte-poor PRP generally better for joints and leukocyte-rich PRP better for tendons? Such simplistic classifications are common. However, the current state of research is considerably more complex.
- For professional users only
- Evidence status: October 2026
- Approx. 14 min. reading time
- 18 specialist sources
01 · Basic question
LR-PRP or LP-PRP: Which is fundamentally better?
Based on the current state of research, neither of the two PRP categories can be considered generally superior.
Knee osteoarthritis
Direct randomized LR-vs. LP trials, as well as several systematic reviews and meta-analyses, are now available. Direct comparisons so far show... no consistent clinical benefit a formulation.
A recent network meta-analysis of 21 RCTs and 2,254 patients also found no statistically significant difference in direct comparison; however, the certainty of evidence for this comparison was rated as low.13
Tendinopathies
The situation is even more inconsistent. Some studies provide signals in favor of LP-PRP, while other analyses see potential advantages for LR-PRP – which are confirmed by more rigorous sensitivity analyses. partially disappear.
Biologically different does not automatically mean clinically superior or inferior.
The designation LR or LP describes one aspect of cell composition. It is neither a complete characterization nor a general quality level.
02 · Terms
What do LR-PRP and LP-PRP actually mean?
LR-PRP stands for leukocyte-rich platelet-rich plasma, LP-PRP for leukocyte-poor platelet-rich plasmaThe terms leukocyte-rich PRP and leukocyte-poor PRP are commonly used.
The two terms appear to represent a clear binary classification. However, in the scientific literature, a different understanding exists. There is no globally uniform absolute leukocyte limit., which is used identically in all classification systems.
The resulting cell composition depends on the starting blood and processing method. The diagram does not depict a specific manufacturing or collection technique.
Even the common classifications define "high in leukocytes" differently:
Dohan Ehrenfest et al. · 20091
The historical classification distinguishes preparations based on the presence of leukocytes and their Fibrin architecture.
PAW Classification · 20122
PAW, on the other hand, takes the Leukocyte concentration relative to baseline blood and additionally captures the neutrophil granulocytes.
Important: "LR-PRP" is not an internationally standardized cell formula. For scientific comparisons, it is more meaningful to specify not only the LR/LP term but also, if possible, the actually measured leukocyte concentration and the underlying definition.
In-depth analysis: Classifications in comparisonCharacterizing PRP correctly: platelet dose, Recovery and cell profile
03 · Cell types
Why the total number of leukocytes alone is insufficient
"Leukocytes" does not refer to a uniform cell population. Therefore, two PRP preparations cannot be considered a single, distinct cell population. similar total number of white blood cells own and yet a markedly different differential blood count exhibit.
Neutrophils
Neutrophils are part of the innate immune response and can release proteolytic enzymes and various inflammatory mediators, among other things. A higher neutrophil count can therefore be associated with an altered cytokine and protease profile.
However, this does not mean that neutrophils should be classified as generally undesirable or "harmful".
monocytes
They also belong to the innate immune system and are discussed in connection with inflammation regulation, tissue remodeling and repair processes.
However, a high or low monocyte count is not in itself a validated marker of quality or efficacy.
Lymphocytes
They receive less attention in the classic LR/LP discussion than neutrophilic granulocytes.
However, cell analyses show that individual preparations classified as LR-PRP can be strongly lymphocyte-dominant.
> 89 %Lymphocytes in the leukocyte differential – at all tested settings of an adjustable commercial preparation system4
< 11 %neutrophil granulocytes in the same examination4
77 %Agranulocytes on average during the characterization of a double-spin LR-PRP6
LR-PRP is not automatically neutrophil-rich PRP.
LR-A · lymphocyte-dominant
High total WBC; the differential is predominantly carried by lymphocytes – as described by cell analyses for individual LR systems.
LR-B · relatively more neutrophils
Similar total WBC count to LR-A, but a different differential. Same "LR" label – different cell composition.
LP · low total WBC
Significantly fewer leukocytes overall. Leukocyte preparations can also differ considerably from one another in terms of platelet count, erythrocyte count, and volume.
Tip: Switch between LR-A and LR-B – the number of cells remains the same, only the composition changes.
04 · Origin of the cell profile
Cell profile results from baseline blood and preparation
The composition of a PRP preparation is not only influenced by the processing system used, but also by the source blood.
Studies with detailed immune cell characterization show differences in granulocytes, monocytes, B and T lymphocytes, as well as other immune cell populations.8 This means that the resulting PRP can differ both between processing systems and between different starting samples.
Methodological consequence: A product name or the designation LR-PRP or LP-PRP is not a complete description of the final product.
05 · Molecular Profile
How is the leukocyte count related to the molecular profile?
Leukocytes are biologically relevant because they themselves contain or can release bioactive molecules. However, studies on PRP show not a one-dimensional pattern, in which "more leukocytes" would automatically be equated with a uniform molecular effect.
Marker overview from three studiesTap a marker to highlight it across studies.
Kobayashi et al. · 20163
Growth factors and proteases
LR-PRP, LP-PRP, and nearly leukocyte-free PRP were compared at comparable platelet concentrations. With increasing leukocyte count, positive correlations with PDGF-BB and VEGF, as well as a pronounced positive relationship with MMP-9, were observed.
increases with the leukocyte count
Further characterization study5
Matrix metalloproteinases also do not follow a simple LR/LP pattern.
LR-PRP was associated with higher concentrations of IL-1 receptor antagonist, PDGF-AA, PDGF-AB/BB, and MMP-1, among others. Other matrix metalloproteinases—including MMP-2, MMP-3, and MMP-12—were, however, higher in the LP-PRP sample.
higher in LR-PRP
higher in LP-PRP
Jayaram et al. · 20239
Signals interpreted as both pro- and anti-inflammatory can occur simultaneously.
LR-PRP and LP-PRP were produced in parallel from the same patients. Among other things, IL-1Ra, IL-4, IL-8, and MMP-9 were elevated in LR-PRP; however, no significant differences were found for TNF-α, IL-1β, IL-6, and IL-10.
higher in LR-PRP
no significant difference
Biological plausibility can explain a hypothesis. It does not prove clinical superiority.
In-depth analysis: molecular levelPRP beyond platelet count: Proteomics and metabolomics
06 · Multiple control variables
Studies often show that LR and LP differ not only in their leukocyte count.
One of the biggest problems with LR/LP literature is that different processing methods are often used. simultaneously several properties of the preparation change.
LR / LPa relevant, but not sufficient, dimension
Parameter 01Total WBC
The parameter that gives the product its name. Without a measured value and a specified definition, it remains unclear what "rich" or "poor" means in the specific preparation.
Varies with the LR/LP status: yesParameter 02Neutrophils
This adds a differential marker to the total WBC value. A higher neutrophil count can be associated with an altered cytokine and protease profile – but is not a universally negative marker.
Varies with the LR/LP status: yesParameter 03Lymphocytes and monocytes
They can dominate the differential of an LR preparation – in a systemic study, the lymphocyte count was over 89%.
Varies with the LR/LP status: yesParameter 04platelet concentration
The effect can differ considerably between LR and LP preparations – in the described epicondylitis RCT, for example, by a factor of 2.7.
Varies with the LR/LP status: yesParameter 05Absolute platelet count
This is determined by the concentration and the volume used. A similar concentration therefore does not necessarily mean a similar total number.
Varies with the LR/LP status: yesParameter 06Erythrocyte fraction
Residual erythrocytes are another cell component that varies depending on the procedure and method of collection.
Varies with the LR/LP status: yesParameter 07Final volume
This affects the total number of cells contained and therefore the comparability of two preparations.
Varies with the LR/LP status: yesParameter 08Recovery
Describes what proportion of platelets from the original blood are found in the preparation.
Varies with the LR/LP status: yesParameter 09activation
Whether and how a preparation is activated is part of the methodological description and differs between protocols.
Varies with the LR/LP status: yesParameter 10Processing steps
The system, centrifugation steps, and settings often change several of the aforementioned parameters simultaneously.
Varies with the LR/LP status: yesA clinical difference between two PRP preparations does not automatically indicate a leukocyte effect.
In-depth analysis: all parameters in detailCharacterizing PRP correctly: platelet dose, Recovery and cell profile
07 · Clinical Evidence
What does the clinical evidence show for knee osteoarthritis?
For the specific LR/LP question, knee osteoarthritis is currently the best examined directly clinical area.
192Patients in the direct RCT by Di Martino et al.
132Patients in the second double-blind RCT
21 RCTsin the Network Meta-Analysis 2026
2.254Patients in this network analysis
-
2022
Direct randomized comparison with 192 patients
Patients with symptomatic knee osteoarthritis of Kellgren-Lawrence grades 1 to 3 were randomized to LR- or LP-PRP. Platelet concentrations in the two preparations were relatively similar, but there was a marked difference in leukocyte count.
After twelve months, there were no significant differences in clinical scores between the groups. Mild local reactions were numerically more frequent after LR-PRP, but the difference was not statistically significant.
No significant difference after 12 months -
2024
Second double-blind RCT with 132 patients
Over twelve months, both groups improved. Some isolated differences were observed at individual time points or for individual measurements, but overall no consistent clinical superiority of one formulation was found.
No consistent superiority -
2024
European Consensus
The ESSKA-ORBIT consensus assessed the evidence for LR versus LP in knee osteoarthritis as inconclusive overall and does not generally support either formulation over the other.
Overall, the evidence is inconclusive. -
2026
Ranking does not equal superiority.
LP-PRP scored higher in certain p-score rankings. However, no statistically significant difference was found in a direct LR/LP comparison; the certainty of evidence for this direct comparison was low.
Methodologically important: A network ranking does not directly demonstrate clinical superiority. Rankings and direct pairwise comparisons do not answer exactly the same question.LP is ahead in the ranking – not directly significant. -
09/2026
A recent subgroup analysis yields an LP signal – but no clear LR/LP response.
The meta-analysis compared PRP with hyaluronic acid. In predefined subgroups, the effects were greater in studies with leukocyte-deficient PRP; at the same time, the heterogeneity of the main results was very high.
In the meta-regression, the degree of osteoarthritis and the number of injections, but not the leukocyte status, were highlighted as statistically confirmed effect modifiers. Furthermore, the studies predominantly involved indirect comparisons of LP-PRP versus HA and LR-PRP versus HA.
LP subgroup signal – predominantly indirect
08 · Compatibility
Are there differences in local reactions?
18,7 %of the PRP cases with reported adverse events – most commonly mild pain and swelling
Safety meta-analysis · 32 RCT publications · 1,268 PRP-treated knees14
Compared to hyaluronic acid, the increased signal for these mild local reactions was observed in the LR subgroup, while LP-PRP showed no significant difference compared to HA. However, the direct LR vs. LP RCTs found no consistently significant difference in safety.
Indirect routeEach one against hyaluronic acid14
LR-PRP vs. HAincreased signal for mild local reactions
LP-PRP vs. HAno significant difference
Some meta-analyses show a stronger signal for temporary local pain or swelling with LR-PRP. However, direct randomized LR/LP comparisons have not yet confirmed a consistent significant difference in safety.
09 · Tendinopathies
What do we know about tendinopathies?
Commonly held rule
LR-PRP for tendons, LP-PRP for joints.
Not justified by current literature as a general matrixLateral epicondylitis: direct RCT with important confounder
A randomized study published in 2026 examined 71 patients and compared LP-PRP, LR-PRP and saline solution.15 LP-PRP showed more favorable results than LR-PRP in several pain and functional parameters.
However, for the interpretation, it is crucial that the preparations not only in leukocyte count distinguished:
The LR-PRP contained approximately 3.8 times more leukocytes, but at the same time 2.7 times fewer platelets than the LP-PRP.15
Consequence: The study cannot prove that the observed difference was caused solely by the leukocytes.
Network meta-analysis 2026: possible LR signal, but not robust
A network meta-analysis with 23 RCTs and 1,484 participants explicitly differentiated between LR- and LP-PRP.16 Initially, LR-PRP appeared to be advantageous in some analyses. However, this advantage did not persist after excluding studies with a high risk of bias.
October 2026: Force endpoints also do not solve the question
Another randomized publication from the same research environment also examined 71 participants.18 At the primary force endpoint, the group differences did not exceed the predefined threshold for clinical relevance.
Since the number of participants, the authors, and the study design show strong overlaps with the previously published 71-patient study, this work should be considered as a separate study. not without detailed cohort comparison can be considered as completely independent confirmation of a second population.
In tendinopathies, the evidence regarding the influence of leukocyte count is inconsistent. Additionally, the compared preparations often differ in other cell and manufacturing parameters.
Furthermore, lateral epicondylitis should not be automatically applied to other tendons. "Tendon" is not a uniform indication.
Lateral epicondylitisnot generally transferable toAchilles' tendonPatellar tendonoperative Rotatorenmanschettenrekonstruktion
10 · Dermatology & Aesthetics
What do we know outside of orthopedics?
For dermatology, hair applications, and aesthetic medicine, direct LR vs. LP evidence is significantly weakerCurrent reviews describe significant differences in study design, preparation, cell composition, activation, and PRP protocols.
This does not provide a reliable basis for statements such as "LP-PRP is fundamentally the better PRP for hair or aesthetic applications".
No transmission without evidence: Results from knee osteoarthritis or tendinopathies should not be automatically transferred to scalp, skin or other aesthetic applications.
11 · Documentation
How should a PRP cell profile be documented?
For scientific comparability, a quantitative characterization more meaningful than the sole designation LR-PRP or LP-PRP.10
Reporting checkWhat information is contained in a preparation description – for example, in a study or in your own documentation? Mark what is present.
The more quantitative data is available, the more comprehensibly a preparation can be scientifically described.
Depending on the specific research question, additional information on lymphocytes and monocytes may be useful. This does not mean that a complete immune cell profile is mandatory in every clinical situation.
What manufacturer and system specifications cannot answer
A PRP system or PRP tubes It can be described with technical precision. However, these specifications do not replace a quantitative analysis of the actual preparation obtained.
Without corresponding laboratory or validation data, no reliable individual statements can be derived from the product name alone regarding:
- Total WBC
- Neutrophil percentage
- Lymphocyte and monocyte proportions
- Residual erythrocytes
- Concentration factor
- Recovery
- absolute platelet count
12 · Classification
What can be deduced at present – and what cannot?
Well-founded
- LR and LP preparations can be biologically different.
- Total WBC does not fully describe the differential blood count.
- LR-PRP may be lymphocyte-dominated.
- Cell profile and preparation influence the molecular composition.
- Direct knee RCTs do not show a consistent LR/LP winner.
- The evidence for tendinopathies is contradictory.
Not generally justifiable
- LR-PRP is generally better for tendons.
- LP-PRP is generally better for joints.
- LP-PRP is generally better for aesthetic applications.
- LR-PRP is generally "pro-inflammatory".
- LP-PRP is generally “anti-inflammatory”.
- The leukocyte count alone explains clinical differences.
| Area | Evidence base for the LR/LP question | Classification of the LR/LP evidence |
|---|---|---|
| Knee osteoarthritis | several direct RCTs as well as meta-analyses | Direct RCTs: no consistent difference in effectiveness |
| Local reactions | Limited direct data; additionally, indirect subgroup analyses. | Possible LR signal indirect; direct RCTs not unambiguous |
| Lateral epicondylitis | Few direct studies with possible cohort overlap | Contradictory results and drug confounding |
| Other tendinopathies | There are hardly any direct LR/LP comparisons. | no basis for a general LR/LP rule |
| Dermatology / Aesthetics | insufficient direct LR/LP comparison data | No reliable general preference can be derived. |
This overview describes the current state of evidence and does not constitute a recommendation for a specific PRP composition or application.
Conclusion: LR and LP are cell profile characteristics, not quality levels.
LR-PRP and LP-PRP are useful descriptive categories. However, they are neither complete biological profiles nor a ranking of "good" or "bad" PRP.
The total number of leukocytes does not indicate which leukocyte subpopulations are dominant. Furthermore, in clinical studies, LR and LP products often differ not only in their white blood cell count. Platelet concentration, absolute platelet count, erythrocyte count, volume, activation, and manufacturing process can also vary.
The clinical evidence reflects this biological complexity. In knee osteoarthritis, direct randomized comparisons have so far shown no consistent difference in efficacy. In tendinopathies, the data are contradictory and further complicated by differing drug characteristics.
For a reliable comparison, PRP should therefore not only be referred to as LR or LP, but should be characterized quantitatively and documented in a comprehensible manner.
Knowledge & Tools
Structuring and classifying PRP cell profiles
If corresponding baseline and final values are available, the PRP classification & reporting calculator can present available information on platelets, leukocytes, Recovery and other parameters in a structured way.
Open PRP Classification & ReportingFAQ
Frequently asked questions about LR-PRP and LP-PRP
What is LR-PRP?
LR-PRP stands for leukocyte-rich platelet-rich plasmaThis refers to PRP with an elevated or present leukocyte count, according to the definition used. There is no globally standardized absolute WBC threshold for LR-PRP.
What is LP-PRP?
LP-PRP stands for leukocyte-poor platelet-rich plasmaThe term describes a preparation with a reduced leukocyte count according to the specific definition or preparation method used. However, different leukocyte preparations can still differ significantly in platelet count, red blood cell count, volume, and other parameters.
At what leukocyte count is PRP considered LR-PRP?
There is no universal threshold value that is used uniformly in all PRP classifications. Therefore, the actual measured WBC value and the definition used are more meaningful than the abbreviation LR alone.
Is LP-PRP better for joints?
Such a general statement is not supported by current evidence. In knee osteoarthritis, direct randomized comparisons of LR vs. LP have so far shown no consistent difference in efficacy. A 2026 network meta-analysis also found no statistically significant difference in a direct comparison; the certainty of evidence for this comparison was low.
Is LR-PRP better for tendons?
There is no general rule for this either. Particularly in lateral epicondylitis, current studies are yielding contradictory results. Furthermore, the investigated LR and LP preparations sometimes differ simultaneously in platelet concentration and other characteristics.
Are leukocytes in PRP harmful?
A blanket statement is not scientifically justified. Leukocytes can contribute to the overall profile with various cytokines, growth factors, and proteases. The resulting clinical significance cannot be derived from the WBC count alone.
Is LR-PRP automatically rich in neutrophils?
No. LR preparations have been described whose leukocyte differential consisted of more than 89% lymphocytes and less than 11% neutrophils.
Which cell values should be documented in PRP.
For scientific comparability, experts recommend, among other things, the documentation of platelet count, total leukocytes, neutrophils, erythrocytes, total volume and volume used or applied, as well as relevant application parameters.
literature
Selected scientific sources
- 1classificationDohan Ehrenfest DM et al. Classification of platelet concentrates. Trends Biotechnol. 2009. PMID 19187989.
- 2classificationDeLong JM et al. Platelet-rich plasma: the PAW classification system. Arthroscopy. 2012. PMID 22738751.
- 3laboratoryKobayashi Y et al. Leukocyte concentration and composition in platelet-rich plasma influences the growth factor and protease concentrations. J Orthop Sci. 2016. PMID 27503185.
- 4laboratoryBaria M et al. Cellular Components and Growth Factor Content of Platelet-Rich Plasma With a Customizable Commercial System. Am J Sports Med. 2019. PMID 30848659.
- 5laboratoryZiegler CG et al. Characterization of Growth Factors, Cytokines, and Chemokines in Bone Marrow Concentrate and Platelet-Rich Plasma. Am J Sports Med. 2019. PMID 31034242.
- 6laboratoryMarathe A et al. Double-Spin Leukocyte-Rich Platelet-Rich Plasma Is Predominantly Lymphocyte Rich With Notable Concentrations of Other White Blood Cell Subtypes. 2022. PMID 35494265.
- 7RCTDi Martino A et al. Leukocyte-Rich versus Leukocyte-Poor Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis. 2022. PMID 35103547.
- 8laboratoryNiemann M et al. Individual immune cell and cytokine profiles determine platelet-rich plasma composition. 2023. PMID 36627721.
- 9laboratoryJayaram P et al. Leukocyte-Rich Platelet-Rich Plasma Is Predominantly Anti-inflammatory Compared With Leukocyte-Poor Platelet-Rich Plasma. 2023. PMID 37199381.
- 10ConsensusHurley ET et al. Experts Achieve Consensus on a Majority of Statements Regarding Platelet-Rich Plasma Treatments. 2024. PMID 37625660.
- 11ConsensusLaver L et al. The use of injectable orthobiologics for knee osteoarthritis: A European ESSKA-ORBIT consensus. 2024. PMID 38436492.
- 12RCTRomandini I et al. Leukocytes Do Not Influence the Safety and Efficacy of Platelet-Rich Plasma Injections for the Treatment of Knee Osteoarthritis. 2024. PMID 39394763.
- 13Network MAXu B et al. Leukocyte-rich versus leukocyte-poor platelet-rich plasma and hyaluronic acid for knee osteoarthritis. 2026. PMID 41629990.
- 14Meta-analysisNakagawa HF et al. Assessment of adverse events and safety associated with intra-articular platelet-rich plasma injections. 2026. PMID 42101047.
- 15RCTWałecka J et al. Molecular background behind lateral elbow pain reduction with Leukocyte-Rich and Leukocyte-Poor Platelet-Rich Plasma. 2026. PMID 41579194.
- 16Network MACha JM et al. Comparative Effectiveness of Focused Versus Radial Extracorporeal Shockwave Therapy and Leukocyte-Poor Versus Leukocyte-Rich Platelet-Rich Plasma for Lateral Epicondylitis. 2026. PMID 42739684.
- 17Meta-analysisAlshehri D et al. Platelet-Rich Plasma Provides Greater Pain Relief and Functional Improvement Than Hyaluronic Acid for Knee Osteoarthritis. 2026. PMID 42744121.
- 18RCTWałecka J et al. Comparative Efficacy of Leukocyte-Rich and Leukocyte-Poor PRP for Lateral Epicondylitis on Isokinetic and Isometric Upper Limb Strength under an Identical Rehabilitation Protocol. 2026. PMID 42829102.
For professional users only. This article provides a scientific overview of PRP cell profiles and current literature. It does not constitute a diagnosis, therapy, dosage, or treatment recommendation. The intended purpose and instructions for use of any medical devices employed, as well as professional assessment within the individual medical context, remain paramount.