What is the 'optimum' optimal additive solution?

Spontaneous formation of clotted material occurs occasionally in all stored red cell units, but larger amounts have been noted in SAG-M optimal additive suspensions. These can be substantially reduced by substitution of the SAG-M solution by a SAG-M/CPDA-1 mixture suggesting that there is insufficient citrate in SAG-M red cell suspensions to completely inhibit coagulation of the residual plasma.