title: Performance characteristics and evaluation of an automated-developed and quantitative, immunochemical, fecal occult blood screening test.
abstract: OBJECTIVE
  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.
authors.affiliation: Gastroenterology Department, Rabin Medical Center, Beilinson Hospital, Petach Tikva, Israel.
authors.forename: Alex
authors.initials: A
authors.lastname: Vilkin
authors.forename: Paul
authors.initials: P
authors.lastname: Rozen
authors.forename: Zohar
authors.initials: Z
authors.lastname: Levi
authors.forename: Amal
authors.initials: A
authors.lastname: Waked
authors.forename: Eran
authors.initials: E
authors.lastname: Maoz
authors.forename: Shlomo
authors.initials: S
authors.lastname: Birkenfeld
authors.forename: Yaron
authors.initials: Y
authors.lastname: Niv
mesh_terms: D000236:Adenoma / Q000175:diagnosis; D018253:Adenoma, Villous / Q000175:diagnosis; D003110:Colonic Neoplasms / Q000175:diagnosis*; D003111:Colonic Polyps / Q000175:diagnosis; D003113:Colonoscopy; D003657:Decision Making; D005243:Feces / Q000737:chemistry; D005260:Female; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007120:Immunochemistry; D007417:Intestinal Polyps / Q000175:diagnosis; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000592:standards; D008875:Middle Aged; D015588:Observer Variation; D009780:Occult Blood; D012004:Rectal Neoplasms / Q000175:diagnosis*; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D006454:Hemoglobins