diagnoser

Diagnoser is the plural form of diagnosis in Swedish and Norwegian. In English, the standard plural is diagnoses. The term is also encountered in medical literature when borrowed from Scandinavian languages.

A diagnosis is the process of identifying the nature of a patient's condition based on observed signs and symptoms, medical history, examination findings, and diagnostic tests.

The diagnostic process typically starts with history-taking and examination, followed by forming a differential diagnosis—an ordered list of possible conditions. Tests such as laboratory assays, imaging studies, and specialized procedures are used to confirm or rule out possibilities.

Diagnoses can be provisional or working during assessment and may become final when criteria are met or when responses to treatment clarify the condition. Some diagnoses are syndromic and describe a constellation of symptoms without specifying a single disease.

Standardized nosologies such as the International Classification of Diseases (ICD) and, in psychiatry, the Diagnostic and Statistical Manual of Mental Disorders (DSM), provide diagnostic criteria and coding to support consistent communication, billing, and research.

Diagnosing carries responsibilities and challenges. Uncertainty is common, and diagnostic errors can occur due to incomplete information, atypical presentations, or cognitive biases. Ongoing monitoring and revision of a diagnosis as new information emerges are integral to clinical care.

In addition to human medicine, diagnostic naming and criteria are used in veterinary medicine, microbiology, and other fields.