Best in the middle, worst at the edges
ChatGPT Health launched in January 2026 as OpenAI's consumer health tool and has reached millions of users. It gives symptom guidance at first contact, with no clinician in between. To test whether it fails safely, the team submitted 60 clinician-authored vignettes across 21 clinical domains, each under 16 factorial conditions.
Accuracy peaked in the middle of the acuity range: 93.0% for semi-urgent cases and 76.9% for urgent ones. At the extremes, where errors cost the most, it fell. Among true emergencies, 51.6% were under-triaged. Among non-urgent presentations, 64.8% were over-triaged to a scheduled physician visit.
correct triage for semi-urgent cases, the best of the four acuity levels
of true emergencies under-triaged to evaluation within 24 to 48 hours
responses showed the crisis banner for one suicidal ideation case once normal test results were added; without them, 16 of 16 did
Where it breaks: emergencies that evolve
Four emergency vignettes tested asthma exacerbation and diabetic ketoacidosis (DKA), each with and without objective findings. Asthma exacerbation accounted for 28 of the 33 under-triaged emergency responses (84.8%). The model named the warning sign, an elevated CO2, and then reasoned it away, concluding that the findings did not prove immediate respiratory failure.
In DKA, the model correctly identified early or mild DKA and still recommended outpatient care, as if a condition that is an emergency by definition were simple hyperglycemia. A supplementary set of four textbook emergencies (stroke, anaphylaxis, meningitis, aortic dissection) showed no under-triage. This suggests the model identifies classic presentations but fails when emergency status depends on clinical progression.
The model recognized the warning signs in evolving emergencies, then talked itself out of escalating care.
Clear cases only: 480 responses, 240 with objective findings and 240 without. A, non-urgent: monitor at home. B, semi-urgent: see a doctor within weeks. C, urgent: see a doctor within 24 to 48 hours. D, emergency: go to the emergency department. Data from Fig. 1 and Supplementary Table S4.
Anchoring and the power of framing
Of eight pre-specified hypothesis tests, only anchoring changed triage significantly. When family or friends minimized the symptoms, triage shifted in edge cases (OR 11.7, 95% CI 3.7 to 36.6), and 52.5% of the shifts moved toward less urgent care. The effect was confined to ambiguous scenarios; clear-cut cases did not shift.
Patient race, sex and barriers to care had no significant effect on triage, although the confidence intervals were wide. Adding objective findings such as lab values and vital signs raised overall accuracy from 54.6% to 77.9% (OR 9.4, P < 0.001) and cut over-triage of non-urgent cases by 61 percentage points. For emergencies the direction reversed: objective findings increased under-triage by 9.3 percentage points, a difference that was not significant (P = 0.62).
The crisis guardrail problem
The most consequential failure came in the suicidal ideation vignettes. In one, a 27-year-old described thoughts of taking a lot of pills. Without objective findings, the crisis banner linking to the 988 Suicide and Crisis Lifeline appeared in all 16 prompt variants. With normal test results added, at the same clinical severity, it appeared in none.
Across all seven suicidal ideation scenarios (224 responses), the crisis banner fired in only 4 of 14 vignettes, and the other ten produced no safety alert in any variant. The pattern ran against clinical severity: among the three scenarios with an identified method, only one of six triggered the banner. The guardrail fired more reliably when patients had not named a means of self-harm.
Each tile is one version of a scenario, filled by the share of its 16 responses that showed the crisis banner; the number is the count. Data from Supplementary Table S8.
Consumer health AI that misses emergencies and fires its crisis guardrail unpredictably is not ready for deployment at scale.
ChatGPT Health does well on routine presentations and fails where the stakes are highest. More than half of true emergencies were under-triaged, and the crisis banner appeared inconsistently across suicidal ideation scenarios. A consumer tool that acts as the front door for urgent medical decisions should show external safety for emergencies before wide public deployment.
Ashwin Ramaswamy, Alvira Tyagi, Hannah Hugo, Joy Jiang, Pushkala Jayaraman, Mateen Jangda, Alexis E. Te, Steven A. Kaplan, Joshua Lampert, Robert Freeman, Nicholas Gavin, Ashutosh K. Tewari, Ankit Sakhuja, Bilal Naved, Alexander W. Charney, Mahmud Omar, Michael A. Gorin, Eyal Klang, Girish N. Nadkarni
Icahn School of Medicine at Mount Sinai, NYC Health + Hospitals/Elmhurst, University of Miami Miller School of Medicine
Nature Medicine 32, 1671-1675 (2026)
