Diagnosis vs prognosis

A diagnosis names the condition a patient has. A prognosis is the forecast of how that condition is likely to progress.

Updated 12 October 2026 (1 minute read)

Summary

  • A diagnosis is worked out from the history, the examination and tests.
  • A prognosis draws on how other patients with the condition have done, and is given as a likelihood.
  • A differential diagnosis is the list of conditions that could explain the symptoms, before tests narrow it down.
  • Patients often ask about prognosis first. They want to know what will happen to them.

Interview questions

  • What is the difference between a diagnosis and a prognosis?
  • A patient asks how long they have to live. How do you answer?
  • How certain can a doctor be about a prognosis?

Practise answering these with a mentor

Our interview preparation has you answer questions like these out loud, with feedback on each answer.

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