CYFRA21-1 (Cytokeratin Fragment) Antigen

A soluble recombinant antigen fragment corresponding to cytokeratin 19, supplied by Antibodies.com as a 50 µg liquid-format reference standard for immunoassay calibration and diagnostic kit development. CYFRA21-1 (also written CYFRA 21-1) is a soluble cytokeratin fragment shed from epithelial tumor cells and is widely studied as a circulating tumor marker, most notably elevated in non-small cell lung cancer and also reported in head and neck, cervical, bladder, and breast carcinomas. Researchers use this antigen to coat microplates, generate standard curves, raise reference antibodies, and spike samples when validating quantitative immunoassays and lateral flow tests. The liquid preparation is best held frozen at -20°C to -80°C in working aliquots to limit freeze-thaw cycles, and handled on ice to preserve epitope integrity. Suitable for ELISA, immunoblotting, immunohistochemistry controls, and in vitro diagnostic research use only.