Background and Objectives: In order to preserve platelet concentrates (PCs) with high yields, a new polyolefin platelet storage container (PL 2410, 1.3L, Baxter, La Chatre, France) with increased gas permeability in combination with, a larger surface area has been developed. The storage capacity was studied with platelets in plasma and platelets additive solution. Materials and Methods: Platelet concentrate pools (PCs) of different yields suspended in either plasma (PCs-PL; n = 30) or PAS II (PCs-PAS; n = 37) were prepared. For preparation of PCs with a low, intermediate and high number of platelets 3, 5 and 6 buffy coat. (BCs) were pooled with different volumes of plasma and 5 and 6 BCs were pooled with different volumes of PAS II, in order to obtain PCs of equal volumes comparable with routine conditions. All PCs were stored on a flatbed shaker at 22 +/-2 degrees C and evaluated on days 1, 2, 5 and 7 by determining platelet and white cell counts, pH (37 degrees C), pO(2), pCO(2) and swirling score. Results: Platelet yields ranged from 1.5 up to 5.5 x 10(11) platelets/U. On day 7 all PCs-PL (n = 4) with platelet yields above 4.5 x 10(11)/U had a pH value below 6.8 (range 5.91-6.79). While 7 of 8 PCs-PAS units with platelet yields above 4.0 x 10(11)/U showed a pH value below 6.8 (range 6.31-6.70). Conclusion: During 7 days of storage in a new 1.3-liter platelet container, the pH was maintained above 6.8 in PCs in plasma with a yield. between 1.5- and 4.5 x 10(11)/U; when PAS II was used, the maximum platelet yield allowed for comparable pH maintenance was Somewhat lower (4.0 x 10(11)/U).