Screening panels for detection of monoclonal gammopathies: confidence intervals.

ported criteria of S/LC -cTnI 6.7 or S/LC -cTnT 5.3 (1, 2 ). Taken together, 55 (15.9%) of the 345 samples were positive for autoantibodies to cardiac troponin I or T isoforms. In these positive samples, 10.9% (6 of 55) were positive for both autoantibodies. The odds of being positive for both autoantibodies increased in the presence of either species; in samples positive for autoantibodies to cTnI, the coprevalence of -cTnT was 18.1% (6 of 33), and in -cTnT–positive samples, the coprevalence of -cTnI was 21.4% (6 of 28). The high coprevalence of autoantibodies to cTnT with autoantibodies to cTnI warrants caution in interpreting the significance of a negative or positive cTnT value that contradicts that of cTnI, and vice versa. One should consider that an autoantibody to antigen may have a negative (interference) or positive (stabilizing) effect on the measurement of the antigen, and that multiple autoantibody/antigen pairs may act independently.