It reacts with Bromodeoxyuridine (BrdU) in single stranded DNA (produced by partial denaturation of double stranded DNA)，BrdU coupled to a protein carrier，as well as free BrdU. BrdU is a thymidine analog，incorporated into cell nuclei during DNA synthesis prior to mitosis. Antibody to BrdU is helpful in detecting S-phase cells，providing useful information on the aggressiveness of tumors.
