Nucleoprotein-coated latex particles in the serologic diagnosis of systemic lupus erythematosus. A comparative clinical and serologic study.

A commercially available test for systemic lupus erythematosus employing nucleoprotein-coated latex particles has been evaluated both clinically and serologically. The sera from all 40 subjects with active SLE had positive latex tests, while all 28 sera from healthy adults had negative latex tests. False-positive latex tests were observed in five of 13 antinuclear factor-positive patients with other chronic inflammatory diseases. Specific DNAase and RNAase digestion of the latex particles suggested the false-positive results were due to DNA moieties, other than native DNA, coating the latex particles.