Platform
Company
Immunology & Autoimmune
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Currently under review
Pending specialist review and validation.
This test measures cysteinylglycine, a small peptide produced when glutathione is broken down, in a complete 24-hour urine collection. The result is expressed as a ratio to creatinine, which helps correct for how concentrated or dilute your urine is.
Cysteinylglycine reflects activity in the gamma-glutamyl cycle and overall glutathione turnover, which are linked to how your body manages oxidative stress. Because many factors influence urinary levels, the ratio provides a more stable way to compare results across people and over time.
Your clinician may order this test to evaluate redox balance and oxidative stress in the context of chronic inflammation, autoimmune conditions, liver enzyme induction, or suspected metabolic or nutritional issues. The ratio can offer clues about glutathione use and recycling, as well as kidney handling of small peptides.
Results are most useful alongside your symptoms and other laboratory findings, such as liver enzymes, kidney function, and related amino acid or peptide markers. Understanding this ratio can help tailor lifestyle or treatment strategies that support your antioxidant defenses and overall health.
If your value is higher than the reference interval, it can suggest increased glutathione breakdown, higher gamma-glutamyl activity, medication effects, alcohol use, or acute illness. Dehydration, strenuous exercise, and collection errors can also affect results. A lower value can be seen with limited precursor availability, lower protein intake, or certain metabolic or kidney factors. Because the result is normalized to creatinine, extremes in muscle mass or kidney function may still influence interpretation.
Discuss your result with your clinician. They may recommend confirming a proper 24-hour collection, reviewing medications and supplements, and correlating with related tests such as liver enzymes, kidney function, plasma amino acids, or markers of inflammation. Management focuses on the underlying cause, and repeat testing may be useful if your health status or treatments change.
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.
Missing any urine during the 24-hour period, spilling, or timing errors can distort the ratio. Follow the container, timing, and storage instructions carefully.
Creatinine normalization reduces dilution effects, but extremes in hydration, muscle mass, or kidney function can still shift the ratio and complicate interpretation.
High protein intake and supplements that affect glutathione pathways, such as N-acetylcysteine or glutathione, can raise cysteinylglycine. Vitamin C or sulfur-containing amino acids may also influence results.
Drugs that induce liver enzymes or impact glutathione use, such as certain anticonvulsants or acetaminophen, and alcohol consumption may increase the ratio.
Infections, autoimmune flares, or other inflammatory states increase oxidative stress and can transiently elevate cysteinylglycine excretion.
Changes in tubular reabsorption, reduced kidney function, or cholestatic and hepatocellular conditions can alter peptide handling and glutathione turnover.
Pregnancy, childhood, older age, and very low or high muscle mass can affect creatinine output, which may subtly influence the creatinine-corrected ratio.
References