Frequency of problems during clinical molecular-genetic testing

Concerns have been raised about the quality of DNA-based genetic testing, b ut few data are available on the problems that occur during clinical geneti c testing. We sought to determine the frequency and severity of such proble ms US laboratories. Problems were defined as events that could or did impai r patient care significantly. Data on the frequency and severity of adverse events during genetic testing were collected from laboratories by anonymou s mail questionnaire and detailed on-site inspection. The surveyed laborato ries (n = 42) reported significant problems in 0.33% of tests performed; th e corresponding value in the inspected laboratories (n = 2) was 0.38%. Sixt y percent of problems occurred in the present phase, 32% in the laboratory phase, and 8% in the posttest phase or multiple phases. The average level o f actual harm resulting from these problems was low. Moderate or high level s of harm occurred in only 0.008% of total cases. No lawsuits, judgments, o r disciplinary actions were taken against the laboratories in 277,000 tests performed. The overall frequency of problems in a given laboratory did not correlate with laboratory age, test volume, accreditation status, proficie ncy testing performance, or institution type (academic, private nonprofit, private for profit). In conclusion, significant problems during genetic tes ting occur infrequently (< 0.5% in most laboratories), and problems resulti ng in moderate or high levels of harm to patients are rare (0.008%).