In the current situation of the Covid-19 pandemic, reliable IgG antibody tests are urgently needed all around the world. Virologists caution against cross-reactivities that could potentially lead to false positives [1,2]. Using ELISAs as an example, we discuss the technical requirements for the development of truly dependable immunological testing methods, since the cross-reactivities debated by many virologists constitute only a small fraction of the actual challenges.
Known causes for “cross-reactivities” and false-positives
Four different causes for false-positives in serological assays are known:
1.Inappropriate capture antigens
2.Cross -reactivities and biochemical interferences
3.Insufficient surface blocking in serological assays
4.Stability of the reagents