Auto-Antikörper-Diagnostik in der Diabetologie - Aktueller Stand der Analytik und klinische Anwendung in Deutschland

The measurement of specific autoantibodies against beta-cell proteins (beta-AAK) has expanded the diagnostic repertoire in diabetology in recent years. The presence of beta-AAK can be interpreted as the first stage of a type 1 diabetes mellitus (DM) without the presence of symptoms or metabolic changes. Since they can often be detected years before clinical manifestation in individuals at high risk of disease, they represent important predictive and early diagnostic markers. Furthermore, the determination of beta-AAK may be indicated for the differentiation of DM type 1 on the one hand and DM type 2 and Maturity-Onset Diabetes of the Young (MODY) on the other hand. Antibody diagnostics are also essential to distinguish autoimmune insulin deficient from severe-insulin-deficient patients, who are clinically very similar but have different prognosis. Estimating the risk of developing DM type 1 in patients suffering from autoimmune endocrinopathies is another area of application for beta-AAK. Analytically, beta-AAK can be determined by very different methods; however, often the results obtained for different test methods are not comparable. Therefore, cut-off values have to be defined by the respective laboratory in order to be able to interpret the obtained results clinically. The comparability of the results is currently aimed at via internationally coordinated harmonization actions. Ring trials (Interlaboratory comparisons) offered to participating laboratories for the determination of antibodies against insulin (IAA), Insulinoma-Antigen 2 (IA-2), Zink transporter-8 (ZnT8) and glutamate decarboxylase (GAD65) can help to improve the analytical quality.