If physicians, nurse practitioners or physician assistants make errors, they can easily go undetected. Health professionals rarely get called out for diagnostic mistakes. Patients may not even realize something has gone wrong until it’s too late. No one really knows how many people are being harmed or killed by serious diagnostic mistakes in primary care settings. Death certificates rarely, if ever, list cause of death as “diagnostic error” or “medical mistake.”
Researchers evaluating primary care visits estimate that about 5 percent of diagnoses in that setting are in error, affecting approximately 12 million adults each year (BMJ Quality and Safety, Sep. 2014). (Note this does not include diagnostic mistakes made in hospitals, specialty clinics or nursing homes.) The researchers concluded that "based upon previous work, we estimate that about half of these errors could potentially be harmful".
A WHO 1993 survey of 34 laboratories worldwide that were supposed to give early warning of epidemic disease revealed that only half the laboratories could diagnose yellow fever reliably, 56% couldn't identify hantaviruses, 82% didn't diagnose California encephalitis, and most laboratories were not equipped at all to test for rarer viral infections, such as Ebola, Lassa and Machupo.
The diagnosis of pulmonary embolism (PE) is missed more than 400,000 times in the USA each year, and approximately 100,000 patients die who would have survived with the proper diagnosis and treatment. It is especially likely to be missed in older patients. The correct diagnosis of PE is made in 30% of all patients who die with massive PE but in only 10% of those who are 70 years of age or older. It is the most commonly missed diagnosis responsible for death in the elderly institutionalized patient. Untreated, approximately one-third of patients who survive an initial pulmonary embolism will die from a future embolic episode.