Capsid proteins define cellular receptor specificity and virus antigenicity. Phosphatases are classified by substrate specificity and sequence homology in catalytic domains. These heterodimers exhibit complex DNA binding specificity. PGK exhibits a wide specificity toward nucleotide substrates. They vary in substrate specificity and subcellular localization. Adjuvants are crucial in affecting the specificity and isotype of the necessary antibodies. Protocadherins function as cell adhesion molecules, essential for synaptic specificity. CT scan has a sensitivity of 94%, specificity of 95%. They are classified according to their ligand specificity, function, localization and/or evolutionary relationships. RNR1 contains both allosteric sites, mediating regulation of substrate specificity and activity. Standards vary according to the specific mediation and the level of specificity that is desired. The primers bind only to these sequences which allows for high specificity. Primer design aims to generate a balance between specificity and efficiency of amplification. Precursor proteins also have an effect on VPg-CRE specificity and stability. Thus, neural signaling is capable of a much higher level of specificity than hormonal signaling.