Metabolomics & Nutrition GSH

Glutathione Index.

Quantitative determination of reduced glutathione (GSH) and oxidised glutathione (GSSG) with calculated redox ratio. Performed by LC-MS/MS from DBS or EDTA whole blood.

Quick Reference
Method
LC-MS/MS
Sample Types
DBS Whole Blood (EDTA)
Analytes

2 analytes + ratio

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What does this test assess?

This method assesses the cellular redox state by measuring both reduced and oxidised forms of glutathione, the body's most abundant intracellular antioxidant.

Clinical indications include:

  • Assessment of oxidative stress capacity and antioxidant reserve
  • Evaluation of cellular redox state in chronic disease
  • Monitoring of N-acetylcysteine (NAC) and glutathione supplementation
  • Assessment of hepatic detoxification capacity
  • Evaluation of oxidative stress in neurodegenerative conditions
  • Monitoring of chemotherapy-induced oxidative damage

Measured analytes

Analyte / GroupComponentsClinical Significance
GSH Reduced glutathione Active antioxidant form; neutralises reactive oxygen species and supports detoxification
GSSG Glutathione disulfide (oxidised) Formed when GSH neutralises free radicals; elevated levels indicate oxidative stress
GSH:GSSG ratio Redox ratio Primary indicator of cellular redox state; a lower ratio indicates greater oxidative stress

About glutathione

Glutathione is a tripeptide (glutamate-cysteine-glycine) and the most abundant intracellular antioxidant in the human body. It plays a central role in protecting cells from oxidative damage, detoxifying xenobiotics, and maintaining the redox state of other antioxidants including vitamins C and E.

GSH

The body's master antioxidant and detoxification molecule

GSH:GSSG

Ratio reflects real-time cellular oxidative stress

Tripeptide

Composed of glutamate, cysteine, and glycine

The ratio of reduced to oxidised glutathione (GSH:GSSG) is one of the most reliable indicators of cellular oxidative stress. Under normal conditions, more than 90% of total glutathione exists in the reduced (GSH) form. A shift toward the oxidised form (GSSG) indicates that the cell's antioxidant capacity is being overwhelmed by reactive oxygen species.

Glutathione depletion has been implicated in a wide range of conditions including neurodegenerative diseases (Parkinson's, Alzheimer's), liver disease, chronic fatigue, autoimmune disorders, and accelerated ageing. It also plays a critical role in phase II hepatic detoxification, conjugating with toxins and drugs to facilitate their excretion.

Analytical technique

The test employs isotope-dilution LC-MS/MS with rapid derivatisation to stabilise the labile thiol groups and prevent ex vivo oxidation. This ensures accurate measurement of the true in vivo GSH:GSSG ratio, which is critical for meaningful clinical interpretation.

Sample information

Available from DBS or EDTA whole blood. Immediate sample stabilisation during collection is essential to prevent artefactual oxidation of GSH to GSSG, which would falsely elevate the oxidative stress reading.

Literature

  1. Forman HJ, et al. “Glutathione: overview of its protective roles, measurement, and biosynthesis.” Molecular Aspects of Medicine, 2009, 30(1-2):1-12. 10.1016/j.mam.2008.08.006
  2. Ballatori N, et al. “Glutathione dysregulation and the etiology and progression of human diseases.” Biological Chemistry, 2009, 390(3):191-214. 10.1515/BC.2009.033

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