IgG detection in the 157 serum samples tested using both procedures showed high concordance: positive (n = 69) and negative (n = 85); three samples (1.9%) yielded discrepant positive results with Abbott ́s SARS-CoV-2 IgG or negative results by the PanbioTM COVID-19 IgG/IgM rapid test device. Here, CD40LG is linked to COVID-19.