A paper-based　visual　fluorescence　immunoassay　is　presented for　the　detection　of　matrix　metalloproteinase-7　(MMP7)　that　is　related　to　renal　cancer.　The　method　is　based　on　the distance-dependent　fluorescence　quenching　of　CdTe　quantum　dots　(QDs)　on　a　nitrocellulose　membrane　by　Ag+　following a　sandwich-type　immunoreaction　on　microtiter　wells　using　silver　nanoparticle　(AgNP)–labeled　secondary　antibody–　and　primary　antibody–coated　microtiter　wells.　The　silver　nanoparticles　captured　in　the　well　are　dissolved　with　HNO3,　while　the　quenching　effect　of　QDs　is　based　on　silver　ion-exchange　reaction　under　365-nm　excitation　light　irradiation.　Increasing concentration　of　released　Ag+,　thus　higher　concentration　of　the　protein,　leads　to　an　increased　distance　of　quenching　on　the　nitrocellulose　membrane.　The　paper-based　immunoassay　by　combination　of　AgNP-assisted　ion-exchange　reaction　with　QD　gives　good　distance-dependent　responses　and　allows　the　detection　of　MMP7　at　a　concentration　as　low　as　7.3 pg mL−1.　The　coefficients　of　variation　are　less　than　6.9%　and　12.4%　for　intra-assay　and　inter-assay,　respectively.　High　specificity　and　long-term　stability　are　achieved　during　the　assay.　Importantly,　the　testing　of　human　serum　samples　using　our　strategy　shows　well-matched　results　with　commercial　human　MMP7　ELISA　kits.　[Figure　not　available:　see　fulltext.].　©　2020,　Springer-Verlag　GmbH　Austria,　part　of　Springer　Nature.