Can the range of pH be a predictive value in the quality of platelet concentrates?

Abstract

Background: We can evaluate in vitro quality of platelet concentrates (PC) by mea-suring different parameters to know what in vitro tests, best determine platelet quality. The pH is one of these parameters and is easy to measure. In 2010 an article was published that described a rating system to evaluate the quality of PC (Van der Meer etal. Vox Sang 2010; 98:517–524). Following up on their work, we studied if the pH ofPC on day 5 of storage can give a predictive value for the quality PC on day 7. Material and methods: In this study we included only PC from buffy coat (BC). A PC-pool was produced from 5 BC isogroup and processed by Orbisac*, the platelets weresuspended in additive solution (AS) in a ratio 35:65 (plasma:AS). In group A) 25 PCs were produced, the AS added was SSP plus. In group B) 14 PCs were treated with pathogen reduction technology (PRT), Mirasol* (riboflavina+UV light, AS: SSP plus). In group C) 22 PCs were treated with PRT Intercept* (amotosalen + UVA light,AS: InterSol), this last group represents our daily routine . All PCS were stored on a flatbed shaker at 22°C. Samples were taken at days 2, 5, 7 and 9 for in vitro test: pH (22°C), CD62p expression, Annexin V binding, swirl, LDH, glucose and lactate concentration. Results: We took into account three parameters (CD62p, annexin V, and lactate concentration), the score of these were combined into one rating value (6 = goodquality, 0 = poor quality). In general PCs in SSP plus had a good score on day 7, 68%of PCs had rating value‡5 and 100% of PCs‡3. When PCs are treated with Mirasol* PRT, using the same AS, the rating value 3, was reached in 50% of PCs on day 7. PCs treated with Intercept* PRT and AS: InterSol, had the rating value 3, in 64% of PCs onday 7. We group together pH ranges on day 5, for three group and analized CD62p, Annexin V and lactate on day 7, this gave a numeric score, rating value. The attached table shows the percentages of PCs within the specified pH ranges on day 5 that meetthe requirements on day 7. All PCs showed ‘‘swirling’’ at the end of storage (swirl‡2). Inour current practice swirl are checked after PCs preparation and the time of issue, when we found PCs with poor swirl (score 1), the value of pH is £6.8 Conclusion: In our experience the AS: SSP plus gives a good metabolic and functional parameters during storage. When PRT was applied there are more activation and lactateproduction in PCs. We can say a pH‡7.1 on day 5, generally provides PCs with acceptable quality on day 7. More studies are needed to check other tests, that could beuseful in a rating system