Ready-to-use ELISA kits are available for the detection of deoxynucleotidyltransferase, terminal, an alias of the protein, DNA nucleotidylexotransferase. The official gene symbol is DNTT. The protein, with a mass of 58.5 kDa and length of 509 residues, is reported to be nuclear. It is a member of the DNA polymerase type-X family and may be known by other names, including: TDT, terminal deoxyribonucleotidyltransferase, terminal deoxynucleotidyltransferase, terminal addition enzyme, and nucleosidetriphosphate:DNA deoxynucleotidylexotransferase.