Cystatin C ELISA Kit (CST3)

Full Name: Cystatin C ELISA Kit (CST3)
Reactivity: Human
Sample Type: Biological Fluids, Serum, Tissue Homogenates, Plasma
Sensitivity: 0.188 ng/ml


Cystatin C (Cys-C, CST3) is a cysteine proteinase inhibitor. It is approx. 12 kDa in molecular weight and is formed predominately by nucleated cells. It is known to be filtered by the glomerulus and then be completely reabsorbed; it is not secreted via the tubes. It is considered as an ideal marker for tubular injury, it can be used both for indicating and indexing of the function of GFR. CysC is filtered by the glomerulus and then be completely reabsorbed, it is not secreted via the tubes. It is considered as an ideal marker for tubular injury, it can be used both for indicating and indexing of the function of GFR.

Cystatin C is an enzyme that stops other enzymes from degrading proteins. Increasing blood levels of folic acid, which can guard against neural tube abnormalities in growing foetuses, is one of the most crucial tasks. In addition to this, CST3 also decreases intestinal absorption and serum levels of cholesterol. It has been used as a marker for estimating GFR and tubular injury when combined with other markers such as creatinine or urea. It is also considered an upstream regulator of many other proteins that have not yet been identified.

The levels of cystatin C found in plasma and serum are found to be inversely related to the amount of GFR. Therefore, by increasing or reducing the about GFR will lead to reducing or increasing the concentration present. Age, sex, food, glucocorticoid insufficiency, and muscle mass have little effect on the amounts seen in the serum. Furthermore, CysC is not found to be present in the urine of majority of animals investigated, however, the concentration is elevated in the urine in individuals that display tubular dysfunction.


Human cystatin C ELISA kit is intended for analysing concentrations of CST3 (cystatin C, Cys-C, cystatin 3, ARMD11, post-gamma-globulin) present in human plasma, tissue homogenates, serum and biological fluid samples.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • One 96-Well Plate: Pre-coated with anti-CST3 antibody.
  • Standards: Lyophilized recombinant.
  • Sample/Standard Dilution Buffer.
  • Biotinylated-labelled Antibody.
  • Antibody Dilution Buffer.
  • HRP-Streptavidin Conjugate (SABC).
  • SABC Dilution Buffer.
  • TMB Substrate.
  • Wash Buffer (25x).
  • Plate Sealer.
  • Product Instructions.


For this cystatin C ELISA kit it is recommended that a standard curve is generated for each assay carried out.

Standard Curve: 0, 0.312, 0.625, 1.25, 2.5, 5.0, 10.0, 20.0 png/ml.
Reactivity: Human
Sensitivity: 0.188 ng/ml
Range: 0.313 – 20 ng/ml
Principle: Sandwich
Application: Research Use Only.


– Specificity: Highly specific for CST3, no cross reactivity or interference between CST3 and analogues was detected.
– Recovery: Serum (87 – 97%), EDTA Plasma (90 – 101%), Heparin Plasma (87 – 97%).
– Linearity: Serum (87 – 100%), EDTA Plasma (88 – 98%), Heparin Plasma (82 – 92%).
– Precison Intra-Assay: CV < 8%.
– Precison Inter-Assay: CV < 10%.
– Stability: Less than 10%.


  1. Cystatin C, kidney function and cardiovascular disease. Pediatr Nephrol. (2006) 21 (9): 1223-30. Bökenkamp A., et al.
  2. Epithelial cell-derived cytokines CST3 and GDF15 as potential therapeutics for pulmonary fibrosis. Death Dis. (2018) 9 (5): 506. Kim YI., et al.
  3. Possible neuroprotective mechanism of human neuroglobin. Ann N Y Acad Sci. (2005) 1053: 220-30. Wakasugi K., et al.
  4. Biochemistry and clinical role of human cystatin-C. Crit Rev Clin Lab Sci. (2004) 41 (5-6): 467-550. Mussap M., et al.


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