Guaiac versus immunochemical tests: faecal occult blood test screening for colorectal cancer in a rural community

Aust N Z J Public Health. 2005 Aug;29(4):358-64. doi: 10.1111/j.1467-842x.2005.tb00207.x.

Abstract

Objective: To describe patient participation and clinical performance in a colorectal cancer (CRC) screening program utilising faecal occult blood test (FOBT).

Methods: A community-based intervention was conducted in a small, rural community in north Queensland, 2000/01. One of two FOBT kits--guaiac (Hemoccult-II) or immunochemical (!nform)--was assigned by general practice and mailed to participants (3,358 patients aged 50-74 years listed with the local practices).

Results: Overall participation in FOBT screening was 36.3%. Participation was higher with the immunochemical kit than the guaiac kit (OR=1.9, 95% CI 1.6-2.2). Women were more likely to comply with testing than men (OR=1.4, 95% CI 1.2-1.7), and people in their 60s were less likely to participate than those 70-74 years (OR=0.8, 95% CI 0.6-0.9). The positivity rate was higher for the immunochemical (9.5%) than the guaiac (3.9%) test (chi2=9.2, p=0.002), with positive predictive values for cancer or adenoma of advanced pathology of 37.8% (95% CI 28.1-48.6) for !nform and 40.0% (95% CI 16.8-68.7) for Hemoccult-II. Colonoscopy follow-up was 94.8% with a medical complication rate of 2-3%.

Conclusions: An immunochemical FOBT enhanced participation. Higher positivity rates for this kit did not translate into higher false-positive rates, and both test types resulted in a high yield of neoplasia.

Implications: In addition to type of FOBT, the ultimate success of a population-based screening program for CRC using FOBT will depend on appropriate education of health professionals and the public as well as significant investment in medical infrastructure for colonoscopy follow-up.

Publication types

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

MeSH terms

  • Age Factors
  • Aged
  • Colorectal Neoplasms / diagnosis*
  • Colorectal Neoplasms / epidemiology
  • Community-Institutional Relations
  • Female
  • Guaiac*
  • Humans
  • Immunochemistry / methods*
  • Indicators and Reagents
  • Male
  • Mass Screening / methods*
  • Mass Screening / statistics & numerical data*
  • Middle Aged
  • Occult Blood*
  • Odds Ratio
  • Patient Acceptance of Health Care / statistics & numerical data*
  • Queensland / epidemiology
  • Reproducibility of Results
  • Rural Population / statistics & numerical data*
  • Sex Factors

Substances

  • Indicators and Reagents
  • Guaiac