Table 6. The Low Leukocyte Group.

Study	Leucocyte characteristic		Anti-coagulant	Activationmethode	Optimal PRP concentration(Vol/Vol and plt/ μ L or fold)	Number used for calculation
Graziani et al. (2006)	Exact leukocyte levels not clarified. “The platelets were automatically leukodepleted by negative charged pall filter.”	Low	ACD-A	Autologous throm.+Ca. gluc.	33.3% of 2.5x ≈ 0.570 × 106	0.570 × 106
Anitua et al. (2009)	Leukocyte level:<200 PLT/μ L (see Table 1 in their article) “care was taken to avoid the buffy coat.”	Low	Sodium citrat	CaCl2	20% of 0.767 ± 95 × 106and0.404 ± 39 × 106	0.767 ± 95 × 106
Jo et al. (2012)	Leukocyte level: Mean RBC and WBC counts reduced from 4.48 ± 0.31 and 6.11 ± 1.56 in whole blood to 0.15 ± 0.06 and 0.01 ± 0.01 in PRP, respectively (P < 001).	Low	ACD	Ca. gluc. orThrom.+ Ca. gluc.	10% of 4.00 × 106(Ca. gluc.)and10% of 8.00 × 106(Ca.gluc. + throm.)	4.00 × 106
						8.00 × 106
Wang et al. (2012)	Exact leukocyte levels not clarified. “Briefly, whole blood was centrifuged at 300g for 10 min and the generated blood monocyte layer was further centrifuged for 10 min and the supernatant was collected.”	Low (?)	Sodium citrate	CaCl2	10% of 1.5-1.9 × 106(4x)	1.7 × 106
Amable et al. (2014)	Exact leukocyte levels not clarified. “Briefly, blood harvested in ACD-containing tubes (BD, #364606) was centrifuged during 5 min at 300 g. After separating the platelet-containing plasma above the buffy coat,…”	Low	ACD	CaCl2	10% of 2.94+/-1.9 × 106	2.94+/-1.9 × 106
Berger et al. (2019)	Leukocyte level: mean 0.1 × 103/μ L (SD 0.1) (Supplementary material)	Low	CPD	Freeze-and-thaw	20% of0.875 × 106(Young group)20% of3.5 × 106(Old group)	0.875 × 106
						3.5 × 106
Wang et al. (2012)	Leukocyte level: 0.37 ± 0.14 ×109/L Leukocyte concentration in PRP significantly lower than that in whole blood (P < 0.001). ( See article Table 2)	Low	EDTA	Throm.+CaCl2	10% of 1.5–3.0 × 106	2.25x 106
Mean optimal PRP concentration						2.7 × 106