Stable Isotope Assays for Nitrogen Metabolism

We apply ¹⁵N- and ¹³C-labeled tracers to capture different aspects of nitrogen handling. These include ¹⁵N-lactose ureide to study colonic nitrogen metabolism, ¹⁵N-ammonia and ¹⁵N-urea to quantify ammonia detoxification and ureagenesis, ¹³C-urea and ¹³C-acetate for urea cycle function, and amino acid tracers such as D₅-phenylalanine to assess metabolic disorders like phenylketonuria (PKU). Together, these tracers provide a comprehensive view of nitrogen metabolism in vivo.

Traditional nitrogen biomarkers measure static concentrations that can fluctuate with diet, environment, or sampling conditions—making them less reliable for mechanistic insight. Stable isotope tracers, in contrast, quantify fluxes: the rates of nitrogen synthesis, conversion, and excretion. This dynamic perspective reveals pathway dysfunction earlier, distinguishes between overlapping metabolic disorders, and generates reproducible endpoints that regulators recognize as more mechanistically meaningful.

Yes. Our nitrogen metabolism protocols are designed to be practical and patient-friendly. Most studies involve either a single oral tracer dose (e.g., ¹⁵N-urea or D₅-phenylalanine) or a short infusion, followed by timed blood, urine, or breath collections. We provide custom tracer kits, site training, and standardized workflows to ensure seamless integration across multi-site clinical trials. The result is reproducible, scalable data collection without adding undue burden on patients or clinical staff.