Histoplasmin-Latex Agglutination Test. II. Results with Human Sera. ∗

Abstract

Summary

This laboratory has now had 10 years experience with the collodion agglutination test for histoplasmosis (3-9). We use it routinely in screening for active histoplasmosis. The test itself is simple to perform and read. However, smaller laboratories or institutions with lesser demand for serologic studies for histoplasmosis find the preparation of collodion particles too time-consuming for their purposes. Commercially-prepared latex particles show similar results as collodion particles when both are sensitized with histoplasmin. It is suggested from these studies that, as in the collodion agglutination test, a 4 + reaction at 1:5 dilution or higher is compatible with active histoplasmosis. In 4 instances 3 + latex agglutinations were observed in sera showing 4+ collodion tests. Thus, at the present time, 3+ agglutinations with latex are placed in the “suspicious” category. As with collodion agglutinations, 1-2 + reactions are considered negative.

Studies are in progress to evaluate further the use of histoplasmin-latex agglutinations in serologic diagnosis of histoplasmosis.