Rapid colorimetric assay for cell growth and survival. Modifications to the tetrazolium dye procedure giving improved sensitivity and reliability

J Immunol Methods. 1986 May 22;89(2):271-7. doi: 10.1016/0022-1759(86)90368-6.


A convenient way to estimate the number of viable cells growing in microtitre tray wells is to use a colorimetric assay and an automatic microplate scanning spectrophotometer. One such assay, developed by Mosmann, depends on the reduction by living cells of tetrazolium salt, MTT, to form a blue formazan product. However the original technique has several technical limitations, namely a less than optimal sensitivity, a variable background due to protein precipitation on adding an organic solvent to dissolve the blue formazan product, and a low solubility of the product. These problems have been overcome by the following modifications: avoidance of serum in the incubation medium, thus overcoming precipitation problems in the organic solvent; avoidance of phenol red in the incubation medium, thus avoiding the use of acid in the final solvent which altered the spectral properties of the formazan; elimination of the medium containing MTT after the reaction and subsequent use of pure propanol or ethanol to rapidly solubilize the formazan; use of a higher concentration of MTT; use of half-area microtitre trays to increase the spectrophotometer readings from a given amount of formazan; use of a more judicious reference wavelength in a dual wavelength spectrophotometer. With these modifications the reliability and sensitivity of the test have been increased to the point where it can in many cases replace the [3H]thymidine uptake assay to measure cell proliferation or survival in growth factor or cytotoxicity assays. Examples of its use in IL-2 assays are given.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Division
  • Cell Line
  • Cell Survival
  • Colorimetry / methods*
  • Colorimetry / standards
  • Culture Media
  • Interleukin-2 / analysis*
  • Lymphocyte Activation*
  • Mice
  • Phenolsulfonphthalein
  • Tetrazolium Salts*
  • Thymidine / metabolism


  • Culture Media
  • Interleukin-2
  • Tetrazolium Salts
  • Phenolsulfonphthalein
  • Thymidine