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Cell Proliferation Kit

Catalog Number: 
1000 Assays

cell proliferation kit from MD Bioproducts

North America: 1-888-USMDBIO
International: +41-44 986 2628

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The cell proliferation kit (XTT) is widely used in cell biology for the study of growth factors, cytokines and media components, for the screening of cytotoxic agents and for lymphocyte activation.



The need for a reliable, sensitive and quantitative assay that would enable analysis of a large number of samples led to the development of methods, such as:

  • use of radioactive thymidine to label DNA in live cells
  • use of Brdu to label DNA in live cells (as a substitute for radioactive thymidine)

The advantages of using MD Bioproducts Cell Proliferation Kit (XTT) can be summarized with the following attributes:

  • easy-to-use: there is no requirement for additional reagents and/or the cell washing procedures
  • speed: multiwell plates and an ELISA reader can be used for reading
  • sensitivity: can be assayed even in low cell concentrations
  • accuracy: dye absorbance is proportional to the number of cells in each well
  • safety: there is no need for radioactive isotopes


  • Kit Components
  • XTT Reagent
  • Activation Reagent



Cell Proliferation Kit Data Insert (PDF, 439 KB)


Alsaid, S. A., DM, A. M., Atwa, M. H., & Soliman, S. M. (2020). Evaluation of the cellular and humoral immune response of sheep vaccinated with inactivated Rift Valley Fever Vaccine Adjuvanted with Montanide gel 01TM. Journal of Applied Veterinary Sciences5(1).


Nagafuku, M., Okuyama, K., Onimaru, Y., Suzuki, A., Odagiri, Y., Yamashita, T. & Inokuchi, J. I. (2012). CD4 and CD8 T cells require different membrane gangliosides for activation. Proceedings of the National Academy of Sciences, 109(6), E336-E342.

How It Works

How It Works: 

The assay is based on the ability of metabolic active cells to reduce the tetrazolium salt XTT to orange colored compounds of formazan. The dye formed is water soluble and the dye intensity can be read at a given wavelength with a spectrophotometer. The intensity of the dye is proportional to the number of metabolic active cells. The use of multiwell plates and an ELISA reader enables testing a large number of samples and obtaining easy and rapid results. The test procedure includes cultivation of cells in a 96-well plate, adding the XTT reagent and incubation for 2-24 hours. During incubation an orange color is formed, the intensity of which can be measured with a spectrophotometer, in this instance with an ELISA reader. The greater the number of active cells in the well, the greater the activity of mitochondria enzymes, and the higher the concentration of the dye formed, which can then be measured and quantitated.