Colloidal gold-based immunochromatographic strip for the detection of digitoxin in human plasma

•An anti-digitoxin monoclonal antibody (mAb) 5D2 was developed and purified, and found to have outstanding specificity, sensitivity, and affinity.•The IC50 and LOD values of mAb 5D2 in human plasma determined by ic-ELISA were 0.205 ng/mL and 0.010 ng/mL.•A colloidal gold-based immunochromatographic assay was developed for the purpose of quickly monitoring the concentration of digitoxin in human plasma.•The strip could be evaluated semi-quantitatively by the naked eye, with a visual LOD (vLOD) of 0.5 ng/mL and a cut-off value of 10 ng/mL.