Urea is hydrolysed by urease to ammonia and carbon dioxide. Ammonia is converted to glutamate by glutamate dehydrogenase (GlDH) in the presence of NADH and ketoglutarate. The reaction is measured kinetically at 340 nm through the decrease in absorbance resulting from the oxidation of NADH to NAD+, proportional to the concentration of urea present in the sample.
