A colonoscopy is a medical testing procedure designed to detect dangerous changes in the colon or rectum. It is not used to check for changes in the nearby prostate gland.

Colonoscopy

According to the National Digestive Diseases Information Clearinghouse, your doctor performs a colonoscopy by inserting a flexible, lighted tube (colonoscope) through the anus and into the rectum and colon. A tiny camera attached to the end of the colonoscope sends live images to an external viewing monitor.

Digital Rectal Exam

During a prostate exam, your doctor may perform a digital rectal exam, which involves using a gloved finger inserted in the rectum to physically detect changes in the prostate, which sits outside the rectum wall.

Transrectal Ultrasound

Your doctor may also perform a transrectal ultrasound, which involves using a cigar-shaped probe inserted into the rectum to bounce sound waves off the prostate and create a detailed image of the gland, according to the Mayo Clinic.

Similarities and Differences

Although these prostate exam techniques require access through the rectum, they differ from colonoscopies, which have an unrelated diagnostic purpose.

Additional Prostate Tests

Additional tests performed to check prostate health include prostate biopsy (tissue sampling) and a PSA test, which measures the presence of an immune system marker linked to increased prostate cancer risks.