Screen failure rate

What does Screen failure rate mean in clinical research?

ICH and CDISC define a screen failure as a potential participant who does not meet the eligibility (inclusion or exclusion) criteria during the screening period.^⁠[1] The screen failure rate is the number of screen failures divided by everyone screened. Sponsors compare sites on it because each failure costs a visit, coordinator time and often a reimbursed procedure, with nothing to show for it.

Rates vary widely with the protocol. In the SYMPLICITY HTN-3 resistant hypertension trial, 880 of 1,415 patients screened (62%) did not meet criteria for randomization, mostly on the blood pressure entry threshold.^⁠[2] In an audit of 15 randomized oncology studies at a cancer center in India, 51% of screened patients failed screening, most often for not meeting inclusion criteria.^⁠[3]

Practical note: many failures are knowable from the chart before the patient comes in, such as an excluded medication, an old lab outside the window or a documented comorbidity. Screening the full record first, including notes, is the job of Identify; see the guide to reducing screen failure.