Comparative evaluation of immunochemical fecal occult blood tests for colorectal adenoma detection.
BACKGROUND
Different immunochemical fecal occult blood tests (FOBTs) have been proposed for noninvasive colorectal cancer screening. Large-scale, colonoscopy-based screening studies that allow evaluation of these tests for the detection of precursor lesions are scarce.


OBJECTIVE
To determine and compare performance characteristics of 6 qualitative immunochemical FOBTs for identifying colorectal adenomas among adults who attended screening colonoscopy examinations.


METHODS
Prospective screening study from January 2006 to December 2007.


METHODS
20 gastroenterology practices in Germany that did screening colonoscopy.


METHODS
1319 participants at average risk for colorectal neoplasia who were undergoing screening colonoscopy (mean age, 63 years; 50% men).


METHODS
6 different qualitative immunochemical FOBTs were done with stool samples collected before bowel preparation for colonoscopy. Performance characteristics (sensitivity, specificity, predictive values, and likelihood ratios) of tests were measured by comparing test results with findings on colonoscopy. Technicians who read the tests were blinded to colonoscopy results, and colonoscopists were blinded to FOBT results.


RESULTS
Overall, 405 participants (31%) had an adenoma and 130 participants (10%) had an advanced adenoma. Performance characteristics varied widely among tests. For the 2 best-performing tests (immoCARE-C [CAREdiagnostica, Voerde, Germany] and FOB advanced [ulti med, Ahrensburg, Germany]), the sensitivity for detection of advanced adenomas was 25% (95% CI, 18% to 34%) and 27% (CI, 20% to 35%), respectively; specificity was 97% (CI, 95% to 98%) and 93% (CI, 91% to 95%); and the positive likelihood ratio was 3.5 (CI, 2.2 to 5.4) and 2.5 (CI, 1.9 to 3.5).


CONCLUSIONS
The study differed from real-life conditions in that stool samples were not directly dissolved in a buffer-filled vial; instead, a small container was used and stool was frozen before testing.


CONCLUSIONS
Qualitative immunochemical FOBTs could be an option for future colorectal cancer screening because they showed better performance characteristics for precursor lesions than guaiac-based FOBTs and are practical for mass screening. However, given the large differences in diagnostic performance among tests, careful evaluation of the different test variants is important.


BACKGROUND
The German Research Foundation (Deutsche Forschungsgemeinschaft) within the framework of a PhD program (Graduiertenkolleg 793).
Hundt
Sabrina
S
The German Cancer Research Center, Heidelberg, Germany.
Haug
Ulrike
U
Brenner
Hermann
H
D000236:Adenoma / Q000175:diagnosis*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D055088:Early Detection of Cancer; D005260:Female; D006138:Guaiac; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D007202:Indicators and Reagents; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D011237:Predictive Value of Tests; D013048:Specimen Handling
D007202:Indicators and Reagents; D006138:Guaiac