Cysteine
CYS
Description
"Cysteine" test measures cysteine levels in your blood to assess detox function, antioxidant support, and protein metabolism. This amino acid helps defend against oxidative stress and supports overall cellular repair. Doctors may order the test when symptoms like fatigue, muscle weakness, or recurrent kidney stones appear. High or low levels can signal metabolic imbalance or poor nutrient absorption. Results guide interventions like supplements or dietary changes. Monitoring cysteine helps support liver detox, energy production, and cellular health.
Category
Amino Acids
Procedure
Invasive
Sample Type
Blood – Plasma
Units
Micromoles Per Liter
Procedure Category
Blood Draw
Test Group
Amino Acid Group, Methylation Group
Test Group Description
Amino Acid Group: Tests in this group analyze amino acid levels in the body, providing valuable insights into protein metabolism and potential genetic or metabolic disorders related to amino acid processing. Methylation Group: Centered on evaluating methylation levels and associated parameters, this group provides insights into methylation processes and their related health implications.
Optimal Range
For All Individuals:
Conventional Unit: 271.00–392.00 µmol/L
SI Unit: 271.00–392.00 µmol/L
Normal Range
For All Individuals:
Conventional Unit: 240.00–360.00 µmol/L
SI Unit: 240.00–360.00 µmol/L
Results That Differ From The Norm (Direct and Indirect Causes)
Inadequate absorption
Insufficient protein consumption
Intestinal maldigestion
Vitamin B6 insufficiency
Key Reasons For Testing
Glutathione Synthesis: Serves as a precursor for producing glutathione, a key antioxidant protecting cells from oxidative damage.
Detoxification: Participates in pathways that remove toxins and heavy metals from the body.
Protein Structure: Supports protein stability and function by forming disulfide bonds.
Antioxidant Defense: Contributes to mechanisms that neutralize free radicals and oxidative stress.
Immune Function: Aids in immune cell activation and cytokine production.
Wound Healing: Supports collagen synthesis for tissue repair and regeneration.
Health Status Conditions It May Be Used To Assess
Currently, this test is not directly associated with any conditions listed on the Health Status page. However, it may be included as part of a broader set of tests linked to specific health conditions.
Some Prominent Medical Labs That May Offer This Test
Please note that this particular test has not been associated with any of the listed prominent medical labs. We recommend enquiring with your private physician or nearest hospital to determine where this specific test can be performed.
References
Important Note
Any medical procedure yielding results outside the norm may be directly or indirectly linked to the conditions outlined on this page. Various factors, including genetics, medication and supplement usage, recent illnesses, pregnancy, pre-test eating, smoking, and stress, can impact the test's outcome. Additionally, factors like false positives, false negatives, inaccurate analyses, and others can influence results.
Reference ranges, which help healthcare professionals interpret medical tests, may vary depending on age, gender, and other factors. They may also differ between laboratories due to variations in instruments and methods used. Optimal ranges are designed for preventive purposes, aiming to identify trends and potential risks early, while normal ranges reflect conventional laboratory values indicating no current disease or pathology. Your healthcare practitioner may have specific reasons for testing that deviate from the usual or may interpret results differently based on individual circumstances. Proper interpretation typically involves considering clinical findings and other diagnostic tests. Hence, it is crucial to provide your healthcare professionals with a comprehensive medical history, consult with them for result interpretation, and follow their guidance for potential re-testing or additional diagnostics.
Disclaimer
This content is provided solely for informative and educational purposes. It is not intended as a substitute for medical advice or treatment from a personal physician. Regarding the interpretation of their medical test results and/or specific health questions, it is recommended that all readers and viewers consult their physicians or other qualified health professionals. The publisher is not responsible for any adverse health effects that may result from reading or following the information in this educational content. Before beginning any nutrition, supplement, or lifestyle program, all viewers, especially those taking prescription or over-the-counter medications, should consult their physician or health care practitioner.
Please note that while prominent lab names are included in this content, we cannot guarantee that these labs offer all the tests mentioned. For confirmation, individuals should contact the labs directly or consult their medical practitioners. The information provided reflects general knowledge at the time of publication and may not include recent updates or emerging research. Readers should verify details with qualified professionals to ensure the most up-to-date and accurate guidance.
[1] El-Khairy L, Ueland PM, Refsum H, Graham IM, Vollset SE; European Concerted Action Project. Plasma total cysteine as a risk factor for vascular disease: The European Concerted Action Project. Circulation. 2001;103(21):2544-2549.
[2] Rehman T, Shabbir MA, Inam-Ur-Raheem M, et al. Cysteine and homocysteine as biomarkers of various diseases. Food Sci Nutr. 2020;8(8):4696-4707.
[3] Stipanuk MH. Role of cysteine in the regulation of mammalian cellular function. J Nutr. 2004;134(12 Suppl):2444S-2449S.
[4] Finkelstein JD. Methionine metabolism in mammals. J Nutr Biochem. 1990;1(5):228-237.
[5] Jacob RA. The integrated functions of vitamin C and cysteine in antioxidant protection. Nutr Res. 1999;19(5):627-637.
[6] Dröge W, Holm E. Role of cysteine and glutathione in HIV infection and other diseases associated with muscle wasting and immunological dysfunction. FASEB J. 1997;11(13):1077-1089.
[7] Smolin LA, Benevenga NJ. The significance of cysteine in nutrition and metabolism. J Nutr. 1981;111(3):412-420.
[8] Rikimaru T, Matsuura T, Matsuo N, et al. Plasma levels of cysteine and glutathione in patients with rheumatoid arthritis. J Rheumatol. 1995;22(7):1280-1283.
[9] Banne AF, Amiri A, Pero RW. Reduced cysteine levels as a risk factor for chronic diseases. J Transl Med. 2003;1(1):7.
[10] Yin J, Ren W, Huang X, et al. Roles of amino acids in gut mucosal functions and health. Adv Nutr. 2017;8(5):723-734.
[11] Townsend DM, Tew KD, Tapiero H. The importance of glutathione in human disease. Biomed Pharmacother.2003;57(3-4):145-155.
[12] Finkelstein JD. The metabolism of homocysteine: pathways and regulation. Eur J Pediatr. 1998;157(Suppl 2):40-44.
[13] Chen LH, Liu Y, Lin Z. Effect of cysteine supplementation on oxidative stress and antioxidant levels in the elderly. J Nutr Health Aging. 2004;8(2):109-113.