Abstract In this article, we evaluate a possible postzone effect for the Histoplasma antigen Lateral Flow Assay (LFA). We re-tested urine samples that were Histoplasma-positive with the LFA, both for an undiluted and diluted sample. Of the twelve samples, a postzone effect was observed in six, and in one sample this led to a false negative result in the undiluted sample. For two samples, dilution of the sample led to a weaker LFA result. We recommend cautiousness when interpreting negative samples based on LFA alone, especially when clinical suspicion of histoplasmosis is high.
Have et al. (Wed,) studied this question.