Colonoscopy is generally considered the criterion standard for test characteristic studies, although it does miss some cases of colorectal cancer.
“In the largest study assessing the test characteristics of the only FIT-DNA test available in the United States (Cologuard; Exact Sciences), its sensitivity and specificity to detect colorectal cancer was 92% (95% CI, 84% to 97%) and 84% (95% CI, 84% to 85%), respectively. Its sensitivity to detect advanced precancerous lesions (advanced adenomas and sessile serrated polyps measuring ≥1 cm) was 42% (95% CI, 39% to 46%), and its specificity to detect “all nonadvanced findings” (including nonneoplastic findings and negative colonoscopy findings) was 87% (95% CI, 86% to 87%).13 A second, smaller study involving Alaska Native individuals confirmed that FIT-DNA testing has higher sensitivity but lower specificity than FITs to detect colorectal neoplasia with 1-time use.” USPSTF
Cologuard Website and video
How often should cologuard be used? Every 3 years, it says.
https://www.cologuardtest.com/faq/how-often-used
How effective is Cologuard?
https://www.cologuardtest.com/meet-cologuard/how-effective-is-cologuard