An assay for testing a sample for the presence and/or amount of an analyte of interest comprising contacting at least a portion of the sample with effective amounts of a primary aptamer comprising a core sequence that binds to the analyte and an anti-aptamer which is complementary to at least a portion of the primary aptamer, wherein the primary aptamer and/or anti-aptamer comprise a detectable moiety(ies) which detect whether the primary aptamer and anti-aptamer are bound to each other or unbound; and wherein a primary aptamer bound to the analyte does not bind to its anti-aptamer, and wherein the primary aptamer comprises a fluorescent label and the anti-aptamer comprises a quencher moiety; wherein the analyte, primary aptamer and anti-aptamer are selected from the group consisting of: (a) the analyte is deoxycorticosterone 21-glucoside and either i. the primary aptamer comprises SEQ ID NO: 62 and the anti-aptamer comprises SEQ ID NO:69, or ii. the primary aptamer comprises SEQ ID NO: 76 and the anti-aptamer comprises SEQ ID NO:77; (b) the analyte is aldosterone (ALDS) and either i. the primary aptamer comprises SEQ ID NO: 63 and the anti-aptamer comprises the complement of SEQ ID NO: 63, or ii. the primary aptamer comprises SEQ ID NO: 79 and the anti-aptamer comprises SEQ ID NO:80; (c) the analyte is cortisol and the primary aptamer comprises SEQ ID NO: 64 and the anti-aptamer comprises the complement of SEQ ID NO: 64; (d) the analyte is testosterone and the primary aptamer comprises SEQ ID NO: 65 and the anti-aptamer comprises the complement of SEQ ID NO: 65; (e) the analyte is Phe-CpRh and the primary aptamer comprises SEQ ID NO: 66 and the anti-aptamer comprises the complement of SEQ ID NO: 66; and (f) the analyte is phenylalanine (Phe) and the primary aptamer comprises SEQ ID NO: 67 and the anti-aptamer comprises the complement of SEQ ID NO: 67. (a) the analyte is deoxycorticosterone 21-glucoside and either i. the primary aptamer comprises SEQ ID NO: 62 and the anti-aptamer comprises SEQ ID NO:69, or ii. the primary aptamer comprises SEQ ID NO: 76 and the anti-aptamer comprises SEQ ID NO:77; i. the primary aptamer comprises SEQ ID NO: 62 and the anti-aptamer comprises SEQ ID NO:69, or ii. the primary aptamer comprises SEQ ID NO: 76 and the anti-aptamer comprises SEQ ID NO:77; (b) the analyte is aldosterone (ALDS) and either i. the primary aptamer comprises SEQ ID NO: 63 and the anti-aptamer comprises the complement of SEQ ID NO: 63, or ii. the primary aptamer comprises SEQ ID NO: 79 and the anti-aptamer comprises SEQ ID NO:80; i. the primary aptamer comprises SEQ ID NO: 63 and the anti-aptamer comprises the complement of SEQ ID NO: 63, or ii. the primary aptamer comprises SEQ ID NO: 79 and the anti-aptamer comprises SEQ ID NO:80; (c) the analyte is cortisol and the primary aptamer comprises SEQ ID NO: 64 and the anti-aptamer comprises the complement of SEQ ID NO: 64; (d) the analyte is testosterone and the primary aptamer comprises SEQ ID NO: 65 and the anti-aptamer comprises the complement of SEQ ID NO: 65; (e) the analyte is Phe-CpRh and the primary aptamer comprises SEQ ID NO: 66 and the anti-aptamer comprises the complement of SEQ ID NO: 66; and (f) the analyte is phenylalanine (Phe) and the primary aptamer comprises SEQ ID NO: 67 and the anti-aptamer comprises the complement of SEQ ID NO: 67.