ELISA SCREENING-TESTS FOR SPECIFIC IGE AND IGG ANTIBODY IN EMPLOYEES EXPOSED TO TRIMELLITIC ANHYDRIDE (TMA)

The objective of the study was to determine whether ELISA screening tests could be developed for specific IgE and IgG antibody in surveillance studies of employees exposed to trimellitic anhydride (TMA). Such tests would obviate the need for radiolabeling and disposal of radioactive wastes. The design of the study was a masked comparison of serologic results of ELISA screening tests with the criterion standard radioimmunoassay (RIA) currently used. The participants were 233 employees of a chemical plant that manufactures TMA. When the screening ELISA serologic results for IgG against TM-human serum albumin (TM-HSA) were compared with those of the RIA, the sensitivity was 92%, the specificity was 93%, the positive predictive value was 62%, and the negative predictive value was 99%. When the screening ELISA serologic results for IgE against TM-HSA were compared with those of the RIA, the sensitivity was 100%, the specificity was 91%, the positive predictive value was 31%, and the negative predictive value was 100%. We conclude that ELISA screening tests for antibody to TM-HSA have sufficient sensitivity, specificity, and predictive value to be useful in surveillance studies of employees exposed to TMA.