The present invention is directed to methods, reagents, and kits for detecting the presence or absence of (or quantifying) target polynucleotide sequences and proteins in at least one sample using encoding and decoding reactions. When a particular target polynucleotide is present in a sample for example, a reaction product is formed in the encoding reaction that includes addressable primer portions. At least one labeling probe and at least one address primer can be employed in the decoding amplification reaction thereby providing a detectable signal value depending upon whether a sequence is present or absent. In some embodiments, the encoding comprises a ligation reaction with linker probes, and single nucleotide polymorphisms (SNPs) are analyzed.