Development and preliminary validation of an antibody filtration-assisted single-dilution chemiluminometric immunoassay for potency testing of Piscirickettsia salmonis vaccines

► A single-dilution immunoassay was set up to measure anti Piscirickettsia salmonis IgM. ► The assay was applied to individual or pooled fish serum and cutaneous mucus samples. ► Serum IgM levels correlated with Relative Percent of Survival against P. salmonis. ► The test identified high vaccine-responders when applied to mucus samples. ► The assay can be considered as a novel potential indirect test for SRS vaccine potency.