A method of detecting at least one target analyte and at least one target nucleic acid in a cell, comprising: a) lysing the cell in a multifunctional lysis buffer to produce a cell lysate; b) detecting at least one target analyte in the cell lysate using a proximity detection assay wherein the proximity detection assay comprises: (i) incubating the cell lysate with a first proximity detection probe and a second proximity detection probe under conditions allowing interaction between the first and second proximity detection probes, wherein the first proximity detection probe comprises a first oligonucleotide moiety and a first analyte binding moiety, and wherein the second proximity detection probe comprises a second oligonucleotide moiety and a second analyte binding moiety; and (ii) detecting the interaction between the first and second proximity detection probes, wherein the interaction between the first and second proximity detection probes comprises at least one method selected from hybridization between the first and second oligonucleotide moieties and ligation of the first and second oligonucleotide moieties and/or wherein the interaction between the first and second proximity detection probes comprises ligation of the first and second oligonucleotide moieties; and c) detecting at least one target nucleic acid in the cell lysate using a quantitative nucleic acid detection assay; wherein (b) and (c) occur in the same vessel; wherein the at least one target analyte is not a nucleic acid; wherein the multifunctional lysis buffer comprises NDSB-201; and wherein the cell lysate is incubated with at least one protease after the hybridization and/or ligation of the first and second proximity detection probes. a) lysing the cell in a multifunctional lysis buffer to produce a cell lysate; b) detecting at least one target analyte in the cell lysate using a proximity detection assay wherein the proximity detection assay comprises: (i) incubating the cell lysate with a first proximity detection probe and a second proximity detection probe under conditions allowing interaction between the first and second proximity detection probes, wherein the first proximity detection probe comprises a first oligonucleotide moiety and a first analyte binding moiety, and wherein the second proximity detection probe comprises a second oligonucleotide moiety and a second analyte binding moiety; and (ii) detecting the interaction between the first and second proximity detection probes, wherein the interaction between the first and second proximity detection probes comprises at least one method selected from hybridization between the first and second oligonucleotide moieties and ligation of the first and second oligonucleotide moieties and/or wherein the interaction between the first and second proximity detection probes comprises ligation of the first and second oligonucleotide moieties; and (i) incubating the cell lysate with a first proximity detection probe and a second proximity detection probe under conditions allowing interaction between the first and second proximity detection probes, wherein the first proximity detection probe comprises a first oligonucleotide moiety and a first analyte binding moiety, and wherein the second proximity detection probe comprises a second oligonucleotide moiety and a second analyte binding moiety; and (ii) detecting the interaction between the first and second proximity detection probes, wherein the interaction between the first and second proximity detection probes comprises at least one method selected from hybridization between the first and second oligonucleotide moieties and ligation of the first and second oligonucleotide moieties and/or wherein the interaction between the first and second proximity detection probes comprises ligation of the first and second oligonucleotide moieties; and c) detecting at least one target nucleic acid in the cell lysate using a quantitative nucleic acid detection assay;