Implementation of blood-based colorectal cancer screening: real-world adherence and outcomes

The overall CRC screening adherence rate remains suboptimal, with only 58% of screen-eligible individuals in the United States up to date with screening. This analysis reports on real-world adherence, test outcomes, and turnaround times for the initial large-scale clinical implementation of a blood-based CRC screening test. Providers ordered the commercially-available, blood-based Shield laboratory developed test (Guardant Health) in their clinics, based on an intended use population of individuals at average risk for CRC, aged 45 years or older. Retrospective review of laboratory orders and test turnaround times for the first 20,000 age-eligible patients was conducted; adherence rate was defined as the number of unique blood samples received out of the number of unique clinical test orders. For the first 20,000 age-eligible patients with a test order, 61% were female individuals; median age was 59 years (range = 45–99). From 20,000 patients, 18,901 provided a blood sample, resulting in 94.5% adherence. Test positivity rate was 9.2%. Median times from placement of an order to blood sample receipt in the testing laboratory and from blood sample receipt in the testing laboratory to a results report were 1 day (range = 0–182) and 15 days (range = 0–83), respectively. Real-world adherence to a blood-based CRC screening test was 95% for the first 20,000 patients, with short median turnaround times for test completion by the patient and results return. These results support the ability of blood-based options to improve adherence.