The invention belongs to but not limited to the technical field of human and
animal health diagnostics, and discloses a binding molecule for
acute infection diagnosis adapted to a point-of-care (POC) scene, an
acute infection diagnosis
system and a kit. The binding molecule is an
antibody, a nano
antibody or an
aptamer (preferably not combined with IgM) which is specifically combined with a J chain of dIgA, steric hindrance and conformation rearrangement are avoided by combining the J chain, and the flexibility of a compound is kept so as to efficiently combine with an
antigen; the
diagnostic system and the kit are adapted to POC scenarios (such as
lateral flow test strips). The problems that POC deployment is difficult, RAT sensitivity is low and dIgA detection efficiency of CSC is low in existing NAT are solved, and the kit has the advantages of being low in cost, high in specificity and good in stability, can be used for rapid diagnosis of multiple acute infections such as
measles and
syphilis, fills up related technical gaps and has high commercial value.