Platform
Company
Immunology & Autoimmune
Review status
Currently under review
Pending specialist review and validation.
This test measures cysteinylglycine, a small dipeptide formed when the antioxidant glutathione is broken down by the enzyme gamma‑glutamyltransferase. Cysteinylglycine is part of the body’s thiol and redox systems, which help manage oxidative stress and support cellular defense.
High‑performance liquid chromatography (HPLC) is used to separate and quantify cysteinylglycine in a blood sample. Results can offer insight into glutathione turnover, liver enzyme activity, and how your kidneys handle small peptides, and are often interpreted along with related analytes.
Your clinician may order this test to evaluate oxidative stress balance, to explore liver or biliary conditions that affect gamma‑glutamyltransferase activity, or to assess nutritional and metabolic factors related to sulfur‑containing amino acids. It can also help contextualize results of related tests such as glutathione, cysteine, and homocysteine.
Findings may support care decisions in settings like chronic inflammation, long‑term medication use that induces liver enzymes, alcohol use, or kidney impairment. In research or specialized clinics, it can help track responses to therapies that target redox pathways or amino acid metabolism.
Your result is interpreted in the context of your symptoms, medical history, diet, medications, and other labs. A higher value can be seen when glutathione is being broken down more rapidly, when liver or biliary enzymes are induced, with alcohol use, or when kidney clearance is reduced. A lower value can occur with limited glutathione availability, dietary insufficiency, malabsorption, or if the sample was not handled promptly.
If your value does not fit your clinical picture, your clinician may suggest a repeat test under fasting conditions, review supplements such as N‑acetylcysteine or glutathione, and check related markers like liver enzymes, kidney function, or other amino acids. Use the result as one piece of information rather than a standalone diagnosis, and discuss next steps tailored to your situation.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Recent high‑protein meals or supplements rich in sulfur‑containing amino acids can shift cysteinylglycine levels. A consistent fasting sample helps reduce variability and improves comparison over time.
N‑acetylcysteine, glutathione, cysteine, methionine, and enzyme‑inducing drugs such as some anticonvulsants can alter glutathione turnover and affect results. Do not stop anything without medical advice.
Chronic alcohol use and certain medications can increase gamma‑glutamyltransferase activity, influencing cysteinylglycine. Your clinician will interpret results alongside liver tests and history.
Reduced kidney clearance can raise circulating small peptides, including cysteinylglycine. Interpreting results with current kidney function tests is important.
Delayed processing, excessive heat, or prolonged storage can oxidize thiols and degrade the analyte, leading to misleading values. Proper collection and timely processing are essential.
Active infection or inflammatory states can shift redox balance and glutathione turnover, temporarily affecting cysteinylglycine. Retesting after recovery may be helpful.
Physiologic changes in pregnancy and aging can modify amino acid handling and redox pathways. Your care team may use clinical context rather than a single threshold.
References