Reproducibility of the immunofluorescent test for antimelanoma antibodies.

The reproducibility of the indirect immunofluorescent test for antibodies to human malignant melanoma cytoplasmic antigens was investigated by testing panels of melanoma and normal sera against cells of each of several different melanomas. Tests were performed in replicate, read blindly by two observers, and repeated on different days. Different observers agreed in the interpretation of replicate assays in approximately 80 to 90% of cases. Variability increased considerably when assays were repeated on different days or when different in as few as 21% of tests. Thus, the results of the indirect immunofluorescent test for melanoma cytoplasmic antibodies must, at the present time, be interpreted with great caution.