Blood Test Added to Colorectal Cancer Screening

The American Cancer Society (ACS) on Wednesday, May 27, 2026, updated its colorectal cancer screening guidelines in the United States, now including blood-based tests as an option for average-risk adults aged 45 and older. This change aims to increase screening rates, particularly among individuals who decline traditional visual or stool-based tests.

The updated recommendations specifically endorse Guardant Health's Shield blood test. While colonoscopies remain the preferred method due to their ability to detect and remove precancerous polyps, the blood test offers an alternative for those unwilling or unable to undergo more invasive procedures. The Shield test demonstrates 83% sensitivity for detecting colorectal cancer but is less effective at identifying precancerous polyps.

This expansion of screening options addresses a critical public health challenge, as approximately one-third of eligible adults currently do not undergo recommended colorectal cancer screenings. Colorectal cancer has become the leading cause of cancer-related deaths among U.S. adults under 50. The ACS emphasizes that blood-based tests should be considered for individuals who would otherwise not be screened, thereby facilitating earlier detection and improving patient outcomes.