Abstract: Disclosed are methods for detecting a target nucleic acid in a sample. The methods include contacting the sample, in the presence of a polymerase and an endonuclease, with a first oligonucleotide that includes, in the 5? to 3? direction, a signal DNA generation sequence, an endonuclease recognition site, and a complementary sequence that has at least one abasic moiety and wherein the complementary sequence has a first complementary sequence that is complementary to at least a portion of the signal DNA generation sequence and a second complementary sequence that is complementary to the 3? end of the target nucleic acid. Also disclosed are methods that include a second oligonucleotide including, in the 5? to 3? direction, a second signal DNA generation sequence, an endonuclease recognition site, and a sequence that is homologous to the first signal DNA generation sequence of the first oligonucleotide and that optionally has at least one abasic site.

Abstract: Disclosed herein are methods, kits, and systems relates for detecting the presence or determining the amount of SARS-CoV-2 nucleocapsid protein in one or more samples obtained from a subject.