A quantitative immunochemical faecal occult blood test is more efficient for detecting significant colorectal neoplasia than a sensitive guaiac test.
BACKGROUND
The sensitive guaiac faecal occult blood test, Haemoccult SENSA (HOS; Beckman Coulter, Fullerton, CA, USA), is our standard screening test for significant colorectal neoplasia. We evaluated an automatically-developed, quantified human haemoglobin immunochemical faecal test, OC-MICRO (Eiken Chemical Co., Tokyo, Japan), to improve test specificity and so reduce the colonoscopy burden.


OBJECTIVE
To compare guaiac faecal occult blood test and immunochemical faecal test diagnostic efficacy and costs for identifying significant neoplasia.


METHODS
Colonoscopies were performed on patients who prepared three daily guaiac faecal occult blood tests with or without immunochemical faecal tests.


RESULTS
Total colonoscopy was performed on 151 subjects who prepared both guaiac and immunochemical faecal tests (group 1) and the positive predictive values (PPV) were also compared to those of 162 subjects undergoing colonoscopy for positive guaiac faecal occult blood tests (group 2). In group 1, comparative sensitivity, specificity, and PPVs for significant neoplasia with guaiac faecal occult blood test were 75%, 34%, and 12% (PPV, 18% for group 2) and with immunochemical faecal test were 75%, 94% and 60% (P < 0.01 for specificity). The number of colonoscopy examinations needed to detect a significant neoplasm because of positive faecal occult blood tests was six to eight with HOS and two with OC-MICRO at 21-31% the cost of evaluating a positive guaiac faecal occult blood test.


CONCLUSIONS
An immunochemical faecal test maintains the high sensitivity of guaiac faecal occult blood test, but significantly reduces the colonoscopy burden and screening costs.
Levi
Z
Z
Department of Gastroenterology, Rabin Medical Center, Beilinson Hospital, Petach Tikva, Israel.
Hazazi
R
R
Rozen
P
P
Vilkin
A
A
Waked
A
A
Niv
Y
Y
D000368:Aged; D003113:Colonoscopy / Q000191:economics / Q000706:statistics & numerical data; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005260:Female; D006138:Guaiac; D006403:Hematologic Tests / Q000191:economics; D006801:Humans; D007150:Immunohistochemistry / Q000191:economics; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
D006138:Guaiac