The Sydney system for lymph node FNA biopsy cytopathology: A detailed analysis of recent publications and meta-analysis and a proposal for the components of an ideal prospective study of a cytopathology reporting system.

Analysis shows the large range is due to heterogeneity of the studies, which suffer from biases and variable statistical analysis that are ultimately included in any meta-analysis, detracting from the usefulness of the risk of malignancy derived by the meta-analysis. Components for ideal analyses of reporting systems are presented.