Table 5.

Assay variability for testing fresh-frozen PBMC samplesa

Reading and component% RSDb
Lower limitEstimateUpper limit
Human readers
 Assay run11.2317.7847.54
 Reader19.1923.3030.75
 Bleedc 18.2220.1322.54
 Run + bleedd 25.8530.4537.76
 Sum of threee 32.2738.1247.86
Computer readings
 Assay run5.998.5515.98
 Bleedc 19.1821.0323.31
 Run + bleedd 20.8223.0926.07
  • a Fresh-frozen PBMCs were isolated and frozen from blood on same day that blood was collected.

  • b Percent RSD = [exp(SDLn) − 1] × 100, where exp is the natural or Naperian antilogarithm and SDLn is the estimated standard deviation from the variance component analysis performed on the natural logarithm of the plate count. Lower and upper limits are based on the 95% confidence interval.

  • c Use if PBMC samples are tested in the same assay run.

  • d Use if the two samples are tested in different assay runs.

  • e Use if two samples are tested in different assay runs counted by different readers.