F12+-ANP can be selectively and rapidly activated by H2S, leading to a large afterglow luminescence turn-on ratio (~122-fold) after pre-irradiation with an 808-nm laser, which is useful for quantifying the H2S concentration in the blood of healthy persons (27.6 ± 2.7 μM), HCC patients (47.0 ± 5.0 μM), and CRC patients (75.9 ± 11.9 μM). The gene discussed is NPPA; the disease is colorectal carcinoma.