Interlaboratory proficiency test in aerobiology using virtual slides – feasibility study

Abstract This study examines the use of Virtual Slide Images with the aim of assessing their efficacy and usability in comparison to traditional microscopy with glass slides for the Quality Control of aerobiological samples. Three glass microscopy slides containing samples of airborne pollen were digitised. Six counters from two laboratories examined the glass slides and their data were used to calculate assigned values and acceptable coefficients of variation (CV%) for seven pollen types. A total of 24 analysts from 12 countries examined the virtual slides using specialist OlyVIA software. Data from traditional glass and virtual slides were entered into tests for repeatability and intralaboratory reproducibility following the norm EN 16868:2019. Participants also completed a questionnaire reflecting on the efficacy and usability of Virtual Slide Images for interlaboratory Quality Control. Data from traditional glass and virtual slides were comparable but CV% were generally larger for virtual slides than glass slides. Participants who examined < 10% of the slide were more likely to produce results outside the limits of the study. The use of virtual slide technology is not for everyone and, in the current study, we found that opinion was polarised but it was interesting to note that there were no differences in response based on years of experience. There are advantages and disadvantages of the two methods, and we recommend virtual slides are used as an adjunct to glass slides for use in aerobiology Quality Control and other aspects of palynological training and assessment.