diagnostic

American  

[dahy-uhg-nos-tik] / ˌdaɪ əgˈnɒs tɪk /

adjective

1. of, relating to, or used in diagnosis.

2. serving to identify or characterize; being a precise indication.

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noun

• diagnostics
  plural

1. diagnosis.

2. a symptom or characteristic of value in diagnosis.

3. Medicine/Medical. a device or substance used for the analysis or detection of diseases or other medical conditions.

4. Computers.

   1. a message output by a computer diagnosing an error in a computer program, computer system, or component device.

   2. a program or subroutine that produces such messages.

diagnostic British  

/ ˌdaɪəɡˈnɒstɪk /

adjective

1. of, relating to, or of value in diagnosis

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noun

1. med any symptom that provides evidence for making a specific diagnosis

2. a diagnosis

Other Word Forms

Derived Forms

• postdiagnostic
  adjective
• prediagnostic
  adjective
• diagnostically
  adverb

Inflected Forms

Nouns

• diagnostics
  plural

Etymology

Origin of diagnostic

1615–25; < Greek diagnōstikós, equivalent to diagnōst ( ós ) distinguished (akin to diágnōsis; see diagnosis) + -ikos -ic

Explanation

Anything diagnostic has to do with disease, especially figuring out which one a patient has. If your doctor wants to run diagnostic tests, then she isn't exactly sure what's wrong with you — so the tests will help diagnose you (figure out what's wrong). The TV show House is all about diagnostic tests: it features illnesses that are unusual and hard to determine. But anything diagnostic is trying to figure out what's wrong. A writing test could be called diagnostic if it's trying to determine how good or bad your writing skills are.

Example Sentences

See Examples For:

diagnostic diagnostics

"Being able to trace signals back to their source is important because a positive blood test needs to be followed by imaging or other diagnostic procedures directed at the right organ," said Li.

From Science Daily ● Aug. 11, 2026

The growing understanding of the mouth-body connection is also leading to new diagnostic tools, prevention strategies and treatments.

From The Wall Street Journal ● Jul. 26, 2026

Brown said he was initially diagnosed with “bad food poisoning” but after multiple visits to urgent care and shedding 20 pounds, the health care team conducted a diagnostic fecal test and discovered Brown had cyclosporiasis.

From Los Angeles Times ● Jul. 14, 2026

New research has also revealed that the condition could be diagnosed by blood test - though further testing is needed before it could be considered as a diagnostic tool available to the public.

From BBC ● Jul. 11, 2026

For most of the twentieth century, medicine had been using the same primitive diagnostic criterion of sex formulated by Klebs way back in 1876.

From "Middlesex: A Novel" by Jeffrey Eugenides

Siemens Healthineers SHL -0.91%decrease; red down pointing triangle cut its full-year outlook for revenue growth, citing a weak performance in its diagnostics segment, but raised its guidance for adjusted earnings due to U.S. tariff refunds.

From The Wall Street Journal ● Jul. 31, 2026

“AI-driven drug discovery, clinical development and diagnostics are beginning to improve productivity across the sector, while life science tools appear to be emerging from a multiyear destocking cycle.”

From MarketWatch ● Jul. 15, 2026

Beyond potential applications in synthetic biology and medical diagnostics, the team demonstrated another possibility by using the 64 synthesized DNA sequences to encode a 169-byte text.

From Science Daily ● Jul. 9, 2026

The diagnostics company is looking to sell its point-of-care testing business unit, valued at $1.5 billion, according to the Financial Times.

From Barron's ● Jun. 29, 2026

I ran both through full diagnostics to confirm they were working correctly.

From "The Martian" by Andy Weir