The authors emphasize: "The diagnostically relevant autoantibodies are heterogenous with respect to their fine specifities, i.e., they recognize a variety of epitopes. As a result, different assays often detect different subpopulations of autoantibodies. The test results for a particular autoantibody specificity can therefore vary from one method to another. This has the consequences in practice:
The possibility of false-negative or false-positive test results can never be reliably ruled out if only one detection method is used to determine the presence of a given autoantibody specificity. Combined screening for antinuclear antibodies by way of indirect immunofluorescence followed by differentiation of autoantibody specificity via enzyme immunoassay and other novel technologies has proven to be an effective approach to serological diagnosis of connective tissue diseases. Control tests should be performed ..."