False-negative rate cannot be reduced by lowering the haemoglobin concentration cut-off in colorectal cancer screening using faecal immunochemical test

Eur J Cancer Prev. 2017 Sep;26(5):365-367. doi: 10.1097/CEJ.0000000000000281.


The aim of this study was to analyse false-negative (FN) results of the faecal immunochemical test (FIT) and its determinants in a colorectal cancer screening programme in Catalonia. We carried out a cross-sectional study among 218 screenees with a negative FIT result who agreed to undergo a colonoscopy. A false-negative result was defined as the detection, at colonoscopy, of intermediate/high-risk polyps or colorectal cancer in a patient with a previous negative FIT (<20 µgHb/g). Multivariate logistic regression models were constructed to identify sociodemographic (sex, age) and screening variables (quantitative faecal haemoglobin, colonoscopy findings) related to FN results. Adjusted odds ratios and their 95% confidence intervals were estimated. There were 15.6% FN FIT results. Faecal haemoglobin was undetected in 45.5% of these results and was below 4 µgHb/g in 94.0% of the individuals with a FN result. About 60% of the lesions were located in the proximal colon, whereas the expected percentage was 30%. Decreasing the positivity threshold of FIT does not increase the detection rate of advanced neoplasia, but may increase the costs and potential adverse effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Colon / diagnostic imaging
  • Colonic Polyps / diagnostic imaging*
  • Colonoscopy
  • Colorectal Neoplasms / diagnosis*
  • Cross-Sectional Studies
  • Early Detection of Cancer / adverse effects*
  • Early Detection of Cancer / economics
  • Early Detection of Cancer / methods
  • False Negative Reactions
  • Female
  • Hemoglobins / analysis*
  • Humans
  • Immunochemistry
  • Logistic Models
  • Male
  • Mass Screening / adverse effects*
  • Mass Screening / economics
  • Mass Screening / methods
  • Middle Aged
  • Occult Blood*
  • Odds Ratio


  • Hemoglobins