Performance characteristics and evaluation of an automated-developed and quantitative, immunochemical, fecal occult blood screening test

Am J Gastroenterol. 2005 Nov;100(11):2519-25. doi: 10.1111/j.1572-0241.2005.00231.x.


Objectives: Guaiac fecal occult blood colorectal cancer (CRC) screening tests (FOBT) are faulted for low sensitivity and nonspecificity for human hemoglobin (Hb). Automated-developed, immunochemical, human Hb FOBT (I-FOBT) is specific, eliminates diet restrictions, and Hb quantification allows selection of a threshold for colonoscopy. Aims were to determine 1) test reproducibility; 2) test stability; 3) intrapatient daily I-FOBT variation; 4) test sensitivity and specificity for neoplasia in 500 symptomatic/high-risk patients undergoing colonoscopy; and 5) to correlate fecal Hb measurements with findings.

Methods: The desktop instrument OC-Sensor (Eiken, Japan) automatically develops and quantitates 50 tests/h for Hb. Patients prepared three tests, which were quantified and then 1) repeatedly re-examined; 2) stored at 4 degrees C or 20 degrees C or 28 degrees C and repeatedly examined; and 3) fecal Hb levels were correlated with colonoscopic findings.

Results: Five I-FOBTs re-examined five times in 1 day had no significant measurement changes. Thirty tests stored for 21 or more days had a decay/day of 0.3%+/- 0.4 at 4 degrees C (NS), 2.2%+/- 1.7 at 20 degrees C (NS), and 3.7%+/- 1.8 at 28 degrees C (p < 0.05). There were intrapatient variations between the three daily I-FOBTs (NS). At the recommended 100 ng Hb/mL threshold, all six cases of CRCs and 20 out of 28 cases of advanced adenomas were detected; evaluated together their sensitivity and specificity were 76.5% and 95.3%.

Conclusions: Desktop, automated-developed, quantitative I-FOBT is now available. Refrigerated OC-Sensor samples are stable for 21 days, easy to prepare and develop and, at the 100 ng Hb/mL threshold, have high sensitivity, specificity, and negative predictive values for significant neoplasia. Suitability for population CRC screening awaits further evaluation.

Publication types

  • Evaluation Study

MeSH terms

  • Adenoma / diagnosis
  • Adenoma, Villous / diagnosis
  • Colonic Neoplasms / diagnosis*
  • Colonic Polyps / diagnosis
  • Colonoscopy
  • Decision Making
  • Feces / chemistry
  • Female
  • Hemoglobins / analysis*
  • Humans
  • Immunochemistry
  • Intestinal Polyps / diagnosis
  • Male
  • Mass Screening / methods*
  • Mass Screening / standards
  • Middle Aged
  • Observer Variation
  • Occult Blood*
  • Rectal Neoplasms / diagnosis*
  • Reproducibility of Results
  • Risk Factors
  • Sensitivity and Specificity
  • Time Factors


  • Hemoglobins