Disclosed herein are polypeptides comprising an extended recombinant polypeptide (XTEN) comprised of a plurality of overlapping sequence motifs and one or more barcode fragments releasable upon protease digestion and detectable from all other proteolytically releasable fragments. Certain embodiments of these polypeptides further comprise a biologically active polypeptide, wherein advantageous embodiments thereof comprise a releasable segment capable of proteolytic cleavage that cleaves the linkage between the XTEN polypeptide and the biologically active polypeptide. Methods of making and methods of using said polypeptides are also disclosed.