Diagnosis may be classified as which three categories?

• A. Confirmed, Probable, Possible
• B. Definitive, Probable, Possible
• C. Certain, Probable, Possible
• D. Verified, Likely, Possible

Answer: (A)

In disease diagnosis and public health surveillance, cases are grouped by how certain the diagnosis is. A confirmed case has definitive evidence, usually laboratory confirmation or clear, established criteria. A probable case has strong clinical evidence plus an epidemiologic link to another case or source, but lacks lab confirmation. A possible case shows compatible symptoms but lacks the lab proof and strong connections that elevate certainty. This three-tier system helps investigators prioritize resources and communicate risk during outbreaks. The other terms used in the distractors aren’t the standard survival definitions, so the best-fitting trio is the one with confirmed, probable, and possible.