TABLE 1.

Comparison of viability and viable cell recovery of cryopreserved PBMC stored at −70°C versus PBMC stored in liquid nitrogen before shipment

ParameterNo. of samplesMedian difference (%) between cells stored at −70°C or in liquid nitrogen (1st quartile; 3rd quartile)P valuea
Frozen viability171.7 (−5.9; 8.1)0.46
Viable cell recovery170.0 (−8.0; 16.0)0.51
  • a Wilcoxon matched-pair signed-rank test. The experiment had >80% power to detect differences of ≥8% in viability and ≥13% in viable cell recovery.