The present disclosure describes compositions of matter comprising a ribonucleoprotein complex comprising a nucleic acid-guided nuclease and a guide RNA, and further comprising and a blocking nucleic acid molecule represented by Formula I, wherein Formula I in the 5′-to-3′ direction comprises: A-(B-L)J-C-M-T-D; wherein A is 0-15 nucleotides in length; B is 4-12 nucleotides in length; L is 3-25 nucleotides in length; J is an integer between 1 and 10; C is 4-15 nucleotides in length; M is 1-25 nucleotides in length or is absent, wherein if M is absent then A-(B-L)J-C and T-D are separate nucleic acid strands; T is 17-135 nucleotides in length and comprises at least 50% sequence complementarity to B and C; D is 0-10 nucleotides in length and comprises at least 50% sequence complementarity to A; and wherein the blocking nucleic acid molecule comprises a sequence complementary to a gRNA.