[Chances and Pitfalls of ANA and ANCA Diagnostics]

Chances and Pitfalls of ANA and ANCA Diagnostics Abstract. In the context of clinical manifestations, if analysed with high quality laboratory methods and correctly interpreted, ANA and ANCA are an essential tool in the differential diagnosis of rheumatic diseases. Neither ANA nor ANCA, however, are pathognomonic markers of rheumatic diseases and they do not have a reliable negative predictive value. Commercially available screening tests such as ENA screen or CTD screen are offered widely. Unfortunately, the results from such tests may in some cases create more insecurity rather than confirming the diagnosis, as the presented case shows.