Background: The red blood cell distribution width (RDW) may predict the prognosis of various cancers. The present study aimed to increase the stool occult blood test (SOBT) sensitivity to predict the results of colonoscopy by the correlation of RDW and polyp stages. Thus, RDW may be used to prioritize patients for colonoscopy.
Materials and Methods: The present study was a retrospective review of 1,311 asymptomatic patients who underwent the SOBT, complete blood count test (CBC), and a colonoscopy with follow-up biopsies if any abnormalities were found. Multinomial logistic regression was used to identify the association between RDW >13.95% and colonoscopy findings.
Results: The average RDW was 13.55±1.58. The results of colonoscopies diagnosed 15 colorectal cancers, 76 high-risk adenomas, 157 low-risk adenomas, 114 non-adenomatous polyps, 13 miscellaneous, and 936 normal. The RDW value was statistically higher in the low risk polyp group compared with the normal group. Higher stages of polyps improved the performance to predict the different types of polyp occurrences using the RDW.
Conclusion: RDW in low-risk adenoma patients was higher compared with the RDW value in the normal population. RDW values can be used to differentiate different types of polyps if there were more participants.

Keywords: Colorectal cancer, Red blood cell distribution width, Colorectal cancer screening, Colorectal polyp