Improving the predictive value of red blood cell storage trials: lessons from the Biomedical Excellence for Safer Transfusion (BEST) Collaborative Trial 41.

BACKGROUND

Storage system trials are conducted for the development and licensure of new red blood cell (RBC) storage systems or to validate new ways of using existing systems. Results from one laboratory are often difficult to reproduce in another laboratory, leading to confusion.

STUDY DESIGN AND METHODS

A large international trial was designed to test the warm overnight hold using common donor collection systems and pooling of units to reduce interlaboratory variability of measures of RBC storage. Methods of measurement were left to the individual laboratories. pH was measured on both laboratory pH meters and clinical blood gas machines. Adenosine 5'-monophosphate (ATP) was measured by a variety of methods.

RESULTS

Intralaboratory variability of measures of pH and ATP were small compared to interlaboratory variability. Initial pH measures between laboratories varied over 0.4 pH units, while RBC ATP concentrations varied 2 to 10 µMol/g hemoglobin. pH variability was partly related to temperature of measurement, but the variability in ATP measures was a problem of both methods and standards.

CONCLUSIONS

Common methods and shared standards between laboratories would improve the interpretation of RBC storage measurements. Improved comparability between major laboratories would speed the development of better RBC storage systems.