Social Media Posts About Medical Tests With Potential for Overdiagnosis

IMPORTANCE: Social media is an influential source of medical information, but little is known about how posts discuss medical tests that carry potential for overdiagnosis or overuse. OBJECTIVE: To investigate how social media posts discuss 5 popular medical tests: full-body magnetic resonance imaging, the multicancer early detection test, and tests for antimullerian hormone, gut microbiome, and testosterone. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study assessed posts on Instagram and TikTok between April 30, 2015, and January 23, 2024, that discussed full-body magnetic resonance imaging, the multicancer early detection test, and tests for antimullerian hormone, gut microbiome, and testosterone. Using keywords on newly created accounts, posts were searched and screened until 100 posts for each test on each platform were identified (n = 1000). Posts were excluded if they did not discuss 1 of the 5 tests or were not in English or if the account holders had fewer than 1000 followers. MAIN OUTCOMES AND MEASURES: The main outcome was information about benefits, harms, and overall tone discussed in the post. All outcomes were summarized descriptively. Logistic regression was used to assess whether the use of evidence or the account holder being a physician or having financial interests influenced how tests were discussed. RESULTS: A total of 982 posts from account holders with a combined 194 200 000 followers were analyzed. Across all tests, benefits were mentioned in 855 posts (87.1%) and harms in 144 (14.7%), with 60 (6.1%) mentioning overdiagnosis or overuse. Overall, 823 posts (83.8%) had a promotional (vs neutral or negative) tone. Evidence was explicitly used in 63 posts (6.4%), personal anecdotes were used in 333 (33.9%), 498 posts (50.7%) encouraged viewers to take action and get the test, and 668 account holders (68.0%) had financial interests. Posts from physicians were more likely to mention harms (odds ratio, 4.49; 95% CI, 2.85-7.06) and less likely to have an overall promotional tone (odds ratio, 0.53; 95% CI, 0.35-0.80). CONCLUSIONS AND RELEVANCE: In this cross-sectional study of social media posts about 5 popular medical tests, most posts were misleading or failed to mention important harms, including overdiagnosis or overuse. These data demonstrate a need for stronger regulation of misleading medical information on social media.