TABLE 3.

Comparability of LPA results obtained with fresh and cryopreserved PBMC

StimulantNo. of subjects/labMedian SI for fresh (frozen) cellsMedian (range) SI ratio for fresh/frozen cellsaMedian (range) correlation coefficientsbNo. (%) of labs with significant correlationsc
Tetanus16-262.0 (1.6)1.10 (0.82 to 1.41)0.62 (0.07 to 0.84)6 (86)
Candida16-2644.2 (38.8)1.31 (0.29 to 4.65)0.63 (−0.41 to 0.85)6 (86)
PWM16-2671.4 (52.8)1.44 (1.14 to 2.03)0.55 (−0.26 to 0.92)6 (86)
  • a SI ratios of the indicated stimulant in fresh versus frozen PBMC were calculated by dividing the SI of the indicated stimulant in fresh PBMC by the SI of the indicated stimulant in cryopreserved PBMC. The data in the column represent the median SI ratio from the median laboratory and the range of median SI ratios at all laboratories.

  • b Spearman correlation analysis of SI from fresh PBMC and SI from frozen PBMC in each laboratory was used to generate the correlation coefficient. The data indicate the median and range of correlation coefficients among all laboratories.

  • c Significance was defined by P ≤ 0.05.