Original Contribution
The American Journal of Gastroenterology (2007) 102, 82–88; doi:10.1111/j.1572-0241.2006.00908.x
Should Patients With Anemia and Low Normal or Normal Serum Ferritin Undergo Colonoscopy?
Mandeep S Sawhney MBBS, MS1,2,3, Thokozeni Lipato MD3, Douglas B Nelson MD1,3, Frank A Lederle MD2,3, Thomas S Rector PhD2 and John H Bond MD1,3
- 1Section of Gastroenterology, Minneapolis VA Medical Center, Minneapolis, Minnesota
- 2Center for Epidemiological and Clinical Research, Minneapolis VA Medical Center, Minneapolis, Minnesota
- 3Department of Medicine, University of Minnesota, Minneapolis, Minnesota
Correspondence: Mandeep S Sawhney, MBBS, MS, Section of Gastroenterology (111 D), One Veterans Drive, Minneapolis, MN 55417.
Received 15 May 2006; Accepted 6 August 2006.
Abstract
BACKGROUND:
Patients with unexplained iron deficiency anemia have a greater prevalence of colonic neoplasia, and should be evaluated for a colonoscopy. The approach to patients with anemia without iron deficiency remains unclear.
OBJECTIVE:
To compare the prevalence of colonic neoplasia in anemic patients with normal ferritin (>50 ng/mL), to those with ferritin 
50 ng/mL, and nonanemic individuals.
METHODS:
Patients referred for colonoscopy for anemia evaluation were stratified into 3 groups: ferritin 50 ng/mL, 51–100 ng/mL, and >100 ng/mL. We compared these groups to each other, and to asymptomatic nonanemic individuals undergoing screening colonoscopy. The prevalence of advanced colonic neoplasia was determined for each group using existing records.
RESULTS:
During the study period, 414 patients who underwent colonoscopy for anemia evaluation and 323 nonanemic individuals who underwent colonoscopy for cancer screening met inclusion criteria. Study subjects were mostly men. The prevalence of advanced colonic neoplasia in subjects with ferritin 51–100 ng/mL was 7.2% (95% CI 2.4–17.9%), similar to 7.9% (95% CI 5.1–11.9%) in those with ferritin 50 ng/mL. The incidence of advanced colonic neoplasia in subjects with ferritin >100 ng/mL was 1.7% (95% CI 0.1–6.6%), similar to 1.2% (95% CI 0.4–3.3%) in the asymptomatic nonanemic group. After adjusting for age, patients with ferritin 50 ng/mL and 51–100 ng/mL were almost 5 times more likely to harbor advanced colonic neoplasia than the other groups. The addition of other laboratory parameters did not improve the predictive value of ferritin.
CONCLUSION:
A ferritin cutoff of 100 ng/mL can be used to determine the need for colonoscopy in men with anemia.
