Extended platelet shelf-life

Extended platelet shelf-life

Transfusion and Apheresis Science 24 (2001) 239±240 www.elsevier.com/locate/transci Extended platelet shelf-life Ruby N. I. Pietersz *, Pieter F. va...

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Transfusion and Apheresis Science 24 (2001) 239±240

www.elsevier.com/locate/transci

Extended platelet shelf-life Ruby N. I. Pietersz *, Pieter F. van der Meer Red Cross Blood Bank Amsterdam, Plesmanlaan 125, PO Box 9137, 1066 CX Amsterdam, The Netherlands

For several reasons the manufacturing of platelet concentrates has changed from single donor units to pools made from 4 to 6 bu€y coats. To the pool additive solution or plasma was added, the platelet supernatant was expressed following a soft spin and dependent on the facility, leukocyte depletion by ®ltration could be performed. The leukocyte-depleted pooled platelet concentrate (LD-PC) was stored in a platelet storage bag of adequate size and material to allow storage with gentle agitation for at least 5 days. Advantages for the use of additive solution may be that more plasma will be available for fractionation, additive solutions are more standardized than plasma, fewer anti-A and anti-B are transfused in case of non-identical ABO transfusion, the protein content is lower which might result in fewer allergic reactions. Disadvantages of additive solution could be that the bu€ering capacity is lower resulting in accelerated deterioration of pH and reduced storage of the platelets, also the survival in vivo might be shortened. Requirements for LD-PC for transfusion to adults of about 60±80 kg body weight are: platelets >240  109 , leukocytes <5  106 (in 97% <1  106 ), red cells <5  109 and volume 150±400 ml. Swirling phenomenon must be present during storage

* Corresponding author. Tel.: +31-20-512-3281; fax: +31-020617-8080. E-mail address: [email protected] (R.N.I. Pietersz).

and is a criterion for issuing. The pH at the end of storage should be between 6.8 and 7.4 (measured at 37°C). We have investigated several platelet storage bags and compared storage of platelet pools in plasma with storage in PAS II. First, storage of identical LD-PC in PAS II obtained by pooling and subsequent dividing into storage bags of various manufacturers was investigated. The study included 1000 and 1500 ml storage bags made of polyole®n (Fresenius Hemocare), 1500 ml storage bags made of CLX plastic (Pall), 1300 ml PL 2410 butyl trihexyl citrate (Baxter), and 1000 ml PVC with DnDP di-n-decyl phtalate plasticizer (Terumo). Platelet concentration was on average 1:04  109 ml 1 in a volume of 285 ml. The pH remained above 6.8 in all containers except the CLX bag during 9 days of storage. Thus, many bags can be applied for extended storage provided they are carefully selected. For the routine in 1995±1998 we made pools of 5 bu€y coats in plasma and removed leukocytes with the Autostope BC ®lter. Due to economical reasons and the demand for plasma, we changed from 1998 to 2000 the procedure to 5 BC in PAS II (about 65% PAS II and 35% plasma), also leukocyte-depleted with the Autostop ®lter. The QC data of the routine production are shown in Table 1. Platelet yield is higher in the pools with plasma and though not signi®cant, the leukocyte depletion seems to be better. Because we want to extend the storage of the platelet pools we have measured pH at day 8 and

1473-0502/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII: S 1 4 7 3 - 0 5 0 2 ( 0 1 ) 0 0 0 6 1 - 1

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R.N.I. Pietersz, P.F. van der Meer / Transfusion and Apheresis Science 24 (2001) 239±240

Table 1 n Volume Platelets Leukocytes Leukocytes Pos culture

Unit

LD-PC in plasma

LD-PC in PAS II

P value

ml 109 >1  106 >5  106

15,037 264  18 342  44 2/917 0/917 3/934

11,834 320  15 312  42 3/694 0/694 2/446

<0.001 <0.001 ns ns ns

found a strong correlation of platelet concentration and pH < 6:8. At day 8 in 18% (n ˆ 232) of the LD-PC stored in plasma had a pH of 6.8 or lower, in PAS II 16% (n ˆ 32). However a sharp decline in pH was found at a concentration of platelets in plasma of >1:4  109 ml 1 . In 15/195 (18%) LD-PC a pH < 6:8 and a concentration <1:4  109 ml 1 was found, whereas 26/37 (70%)

had a pH < 6:8 and a platelet concentration >1:4  109 ml 1 . In PAS II the same drop in pH occurred at a platelet concentration of 1:1  109 ml 1 . In conclusion, extended shelf-life of platelets depends on the platelet storage bag, the platelet concentration and the storage medium. Bacterial contamination should be monitored in all PC.