Clinical Factors Associated with a Positive Immunochemical Fecal Occult Blood Test and Negative Colonoscopic Findings
Kasiruck Wittayasak MSc1, Bunchorn Siripongpreeda MD2,3, Prassanee Sattayarungsee MSc2, Kamonwan Soonklang MSc2, Kanlayanee Krohkaew MNS2, Chanisara Suebwongdit RN2, Suchada Panaiem RN2, Wilaiwan Srikun BSc1, Nawanart Rittisupatum BSc1
Affiliation : 1 Data Management Unit, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand 2 Chulabhorn Hospital, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand 3 Faculty of Medicine and Public Health, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand
Objective : To identify clinical factors associated with a positive immunochemical fecal occult blood test [iFOBT] followed
by a negative colonoscopic finding in a colorectal cancer [CRC] screening program.
Materials and Methods : A retrospective study was performed of data collected from a CRC screening program in 2013.
Participants were aged 50 to 65 years, with no previous history of colonoscopy. Their stool occult blood was tested at 0, 3,
and 6 months, and if there was a positive result they underwent colonoscopy.
Results : There were 1,827 participants, among whom 379 cases had a positive iFOBT. The 356 cases that had complete data
included 116 men (32.58%) and 240 women (67.42%). Their mean age was 57.56+4.38 years. In multivariate analysis,
factors associated with a positive iFOBT and a negative colonoscopic finding were adjusted by sex, age, abnormal signs, and
CRC family history. The presence of anemia was significantly associated with a positive iFOBT and a negative colonoscopic
finding (adjusted OR, 1.44; 95% CI, 1.05 to 1.99; p = 0.026).
Conclusion : In patients with anemia who have a positive iFOBT and a negative colonoscopic finding, the physician should
attempt to find possible causes of the unexplained anemia.
Keywords : Positive immunochemical fecal occult blood test, Negative colonoscopic finding, Hemorrhoids, Anemia
