Issues with percent coverage-based non-viable fungal analysis and new methodology for enumeration-based analysis

Abstract

The choices of methodology for analysis of non-viable fungal surface samples are yet to be agreed upon. The two main types of analysis of non-viable fungal (gross fungi) samples can be generally categorised as counting based (enumeration of fungal structures) or categorization based (such as percent coverage estimates or fungal rating categories). We present evidence of flaws in the percent coverage methodology due to a strong dependence on individual analyst’s subjective estimates. By using image analysis and a survey of analysts we show the high variability between analysts’ percent coverage estimates. We also propose an enumeration-based methodology which attempts to address problems in current counting-based methods by using a semi-random grid pattern of fields of view rather than a traverses-based approach.