The intraand
inter-examiner reproducibility for each protocol was estimated using the Intraclass
Correlation Coefficient (ICC) and its confidence interval (95% CI). Based on the results
obtained for both phospholipase and SAPs, there appears to be no consensus on the
protocol chosen for each particular examiner. Measuring the colonies in triplicate may
be the main factor associated with the increase in measurement accuracy and should
therefore take precedence over measuring only one colony. When only one examiner is
responsible for taking measurements, a standard protocol should be put in place and the
statistical calibration of this researcher should be done prior to data collection. However,
if two or more researchers are involved in the assessment of agar plates, our results
suggest that the protocols using software to undertake plate reading is preferred.