# diagnose

/ˌdaɪəɡˈnoʊs/ (US) · /dˌaɪəɡnˈəʊz/ (UK)

Source: https://englishreference.com/word/diagnose
Updated: 2026-08-08

## Senses

### 1. medical identification

verb · CEFR B2

to identify a disease or illness by looking at a person's symptoms.

For teachers: to identify the nature of an illness or other medical condition by examination of the symptoms. Transitive, taking the condition or the patient as the direct object.

- The doctor diagnosed her with a mild allergy after she developed a rash.
- Specialists spent weeks running tests before they could accurately diagnose the rare genetic condition affecting the patient's nervous system.

Usage: Commonly used in the passive voice: 'He was diagnosed with...'

### 2. technical or general problems

verb · CEFR C1 · Technical

to find the exact cause of a problem with a machine, a system, or a situation.

For teachers: to determine the cause of a mechanical failure, technical fault, or systemic problem through systematic analysis.

- The mechanic used a computer to diagnose the fault in the car's engine.
- The consultant was hired to diagnose the underlying issues that were causing the company's sudden drop in productivity.

Usage: Often takes an abstract noun like 'problem', 'fault', or 'issue' as a direct object.

## Examples

- The doctor needs more tests to diagnose the illness.
- After reviewing the blood results, the specialist was able to diagnose the patient with a rare vitamin deficiency.
- While modern imaging technology allows clinicians to diagnose structural abnormalities with high precision, many neurological conditions still require a longitudinal observation of behavioral symptoms to confirm.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.