• Diagnostic errors
• Patient-centred care
• Patient safety

It looks like diagnosis triggers may be gaining traction. Building on their earlier efforts,1 ,2 a team of investigators based in Houston reports on their latest effort to apply electronic screens—so called ‘triggers’—to large clinical databases, to identify cases of potential diagnostic errors.3 They searched nearly 300 000 patients’ records over a 12-month period at two large health systems with comprehensive electronic health records. They sought patients who had one of four ‘red flag’ findings for prostate or colon cancer—elevated prostate specific antigen (PSA), positive fecal occult blood test (FOBT), rectal bleeding (haematochezia), and iron deficiency anaemia. They then used a refined electronic algorithm to cull out patients who (1) were already known to have prostate or colorectal cancer, or (2) had evidence of appropriate follow-up testing or referral. This process left roughly 1500 patients with one of the four red flags potentially unaddressed. Thus, searching an enormous haystack of 300 000 patients, they found roughly 1500 possible ‘needles’–patients who may have had their diagnosis of colon or prostate cancer delayed or overlooked entirely.

Their next step was manual chart review. They had hoped that the yield of their electronic screen for diagnostic failures (‘positive predictive value’) might approach 35%, meaning that at least one out of every three ‘screen positive’ charts would have evidence for care improvement opportunities. Instead they were pleasantly surprised that fully …