Can I sue a doctor for misdiagnosis in California?

Yes — when the diagnostic failure fell below the standard of care and caused real harm. A missed or delayed diagnosis is negligence only if a reasonably careful practitioner in the same field would have identified the condition; California recognized failure-to-diagnose liability in Landeros v. Flood (1976) 17 Cal.3d 399.

Misdiagnosis claims turn on two expert-proven elements. First, breach: diagnosis involves judgment, so a wrong conclusion is actionable only when a reasonably careful physician in the same field, given the same presentation, would have ordered the tests or reached the diagnosis that was missed — the principle applied in Landeros v. Flood (1976) 17 Cal.3d 399. Second, causation, usually the harder element: the patient must show the delay itself changed the outcome, such as a cancer found at a later stage or a stroke window missed, not merely that the disease progressed as it would have anyway. Both elements require qualified medical expert testimony. The deadlines are unforgiving: Code of Civil Procedure section 340.5 allows one year from when the patient discovered or reasonably should have suspected wrongdoing, within a three-year outer limit, and section 364 requires 90 days' pre-suit notice. Complete records under Health and Safety Code section 123110 are the practical first step, and MICRA's cap shapes recoverable non-economic damages.

Authority: Landeros v. Flood (1976) 17 Cal.3d 399