The proper pH for a unit of platelets must be above 6.

The proper pH for a unit of platelets must be above 6.2. According to the FDA, accurate pH measurement is time dependent, and samples should be tested within 1 hour of sampling, or as suggested by the manufacturer of the pH measurement system. It is recommended that a pH meter or gas analyzer be routinely used rather than pH (nitrazine) paper. However, if the laboratory chooses to determine pH measurements with nitrazine paper, the selected paper should read in increments of one-tenth units, or it may provide inaccurate measurements. Maintaining proper pH requires at least 35 ml, but preferably 50-70 ml of plasma per platelet unit.

In order to prevent a loss of viability in platelet concentrates during storage the pH must be maintained above: