Abstract

Laboratory testing is of great value when evaluating a patient with a suspected autoimmune disease. The results can confirm a diagnosis, estimate disease severity, aid in assessing prognosis and are useful to follow disease activity. Components of the laboratory exam include complete blood count with differential, comprehensive metabolic panel, inflammatory markers, autoantibodies, and flow cytometry. Currently, autoimmunity laboratories are very vibrant owing to the constant and increasing availability of new tests, mainly due to the detection of new autoantibodies. The main characteristic that differentiates the autoimmunity laboratory from other laboratories is the use of immunoassays such as enzyme-linked immunosorbent assay (ELISA), as basic techniques which determines antibodies (autoantibodies) and not antigens. For this reason, immunoassay techniques must employ antigens as reagents. However, over the last few years, a significant trend at autoimmunity laboratories has been the gradual replacement of immunofluorescence microscopy by immunoassay. Nowadays the revolution of new technology has taken place significantly, for examples; recombinant DNA technology has allowed the production of large quantities of antigens for autoantibody analysis. Flow cytometry for the analysis of microsphere-based immunoassays allows the simultaneous measurement of several autoantibodies. In the same way, autoantigen microarrays provide a practical means to analyse biological fluids in the search for a high number of autoantibodies. We are now at the beginning of an era of multiplexed analysis, with a high capacity of autoantibody specificities. The future tendency in this field will include immunoassays with greater analytical sensitivity, specificity, simultaneous multiplexed capability, the use of protein microarrays, and the use of other technologies such as microfluidics.

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