An insight into iTRAQ: Where do we stand now?

Caroline Evans Evans, Josselin Noirel, Saw Yen Ow, Malinda Salim, Ana G. Pereira-Medrano, Narciso Couto, Jagroop Pandhal, Duncan L. Smith, Trong Khoa Pham, Esther Karunakaran, Xin Zou, Catherine A. Biggs, Phillip C. Wright

Research output: Contribution to journalReview ArticleResearchpeer-review

194 Citations (Scopus)


The iTRAQ (isobaric tags for relative and absolute quantification) technique is widely employed in proteomic workflows requiring relative quantification. Here, we review the iTRAQ literature; in particular, we focus on iTRAQ usage in relation to other commonly used quantitative techniques e.g. stable isotope labelling in culture (SILAC), label-free methods and selected reaction monitoring (SRM). As a result, we identify several issues arising with respect to iTRAQ. Perhaps frustratingly, iTRAQ's attractiveness has been undermined by a number of technical and analytical limitations: it may not be truly quantitative, as the changes in abundance reported will generally be underestimated. We discuss weaknesses and strengths of iTRAQ as a methodology for relative quantification in the light of this and other technical issues. We focus on technical developments targeted at iTRAQ accuracy and precision, use of 4-plex over 8-plex reagents and application of iTRAQ to post-translational modification (PTM) workflows. We also discuss iTRAQ in relation to label-free approaches, to which iTRAQ is losing ground. [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)1011-1027
Number of pages17
JournalAnalytical and Bioanalytical Chemistry
Issue number4
Publication statusPublished - Sep 2012
Externally publishedYes


  • Isotopic impurities
  • Label-free
  • Modelling
  • MS/MS instrumentation
  • PTMs
  • Ratio underestimation
  • Relative quantification
  • Shotgun proteomics
  • Statistical validation

Cite this

Evans, C. E., Noirel, J., Ow, S. Y., Salim, M., Pereira-Medrano, A. G., Couto, N., Pandhal, J., Smith, D. L., Pham, T. K., Karunakaran, E., Zou, X., Biggs, C. A., & Wright, P. C. (2012). An insight into iTRAQ: Where do we stand now? Analytical and Bioanalytical Chemistry, 404(4), 1011-1027.