diagnostic
gb/dˌaɪəɡnˈɑstɪk/ us/dˌaɪəɡnˈɑstɪk/
B2
English
~ 5800
Senses
0 senses
adjective
technical
B2
property
1
used to find cause of problem
Describing tests, tools, or methods that help find what is wrong, especially in medicine or machines.
Usage pattern:
a diagnostic [test/tool/procedure]
Common mistake:
Learners often confuse "diagnostic" (adjective) with "diagnosis" (noun). Use "diagnostic" before a noun (e.g., "diagnostic test"), and "diagnosis" as a thing you receive (e.g., "a diagnosis of diabetes").
Synonyms
investigative (Stresses careful searching or examination, not specifically linked to medicine or technology.)
Antonyms
therapeutic (Focuses on treating a problem rather than finding out what it is.)
Collocations
diagnostic test
|diagnostic tool
|diagnostic imaging
|diagnostic procedure
|diagnostic equipment
|diagnostic report
Themes
medicine
|science
|technology
|health
Examples
- The doctor ordered several diagnostic tests to confirm the infection.
- Modern cars have built‑in diagnostic systems that detect engine problems.
- We used a diagnostic tool to find the source of the network failure.
- The clinic recently invested in new diagnostic imaging machines.
- Accurate diagnostic procedures are essential for effective treatment.
Learner examples
- The hospital did a diagnostic test on her blood.
- A mechanic used a diagnostic computer to check my car.
- Good diagnostic equipment can find problems early.
- They ran a diagnostic scan to see his lungs.
- This diagnostic tool shows where the problem is.
adjective
formal
C1
property
2
clearly showing a particular condition
Clearly showing that something is a certain disease, problem, or type, often used as "diagnostic of".
Usage pattern:
diagnostic of [a disease/condition/type]
Common mistake:
Learners sometimes say "diagnostic to" instead of "diagnostic of". In this sense, the correct pattern is "diagnostic of" a disease, problem, or type.
Synonyms
indicative (General word for showing something; "diagnostic" is stronger and often used in technical or scientific contexts.)
Antonyms
nondiagnostic (Describes a sign or test result that does not clearly point to a specific condition.)
Collocations
diagnostic of
|highly diagnostic
|not diagnostic of
|clinically diagnostic
Themes
science
|analysis
|medicine
|health
Examples
- Frequent nighttime coughing can be diagnostic of asthma in children.
- This pattern of errors is highly diagnostic of a memory leak in the software.
- The rash alone is not diagnostic of the disease without blood tests.
- Such behavior is often diagnostic of a wider communication problem in the team.
- The imaging findings are almost pathognomonic, clearly diagnostic of the condition.
Learner examples
- High blood sugar is diagnostic of diabetes.
- This kind of crack is diagnostic of old concrete.
- A dry cough is not always diagnostic of COVID‑19.
- That sound is diagnostic of an engine problem.
- These signs are diagnostic of stress at work.
Noun
technical
C1
entity
3
test used to find a problem
A test or check that finds what is wrong in a person, machine, or system.
Usage pattern:
to run a diagnostic on [something]
Common mistake:
Learners may say "make a diagnostic" instead of "run a diagnostic" or "do a diagnostic". In technical English, "run a diagnostic" is the most natural collocation.
Synonyms
test (Very general; "diagnostic" is more specific to finding the cause of a problem.)
Antonyms
treatment (Refers to actions taken to fix a problem, not to discover it.)
Collocations
run a diagnostic
|computer diagnostic
|engine diagnostic
|full diagnostic
|hardware diagnostic
|system diagnostic
Themes
medicine
|technology
|science
|health
Examples
- The mechanic ran a diagnostic on the car before giving an estimate.
- IT support asked me to send the results of the system diagnostic.
- A quick diagnostic showed that the battery was failing.
- Before we replace the part, we should do a full diagnostic.
- The software includes a built‑in diagnostic for common network issues.
Learner examples
- The garage did a diagnostic on my car.
- We ran a diagnostic on the computer.
- The diagnostic showed a problem with the hard drive.
- A quick diagnostic can save repair time.
- She asked the technician to do a full diagnostic.
Grammar
Dictionary form
diagnostic
IPA
GB/dˌaɪəɡnˈɑstɪk/
US/dˌaɪəɡnˈɑstɪk/
Syllables & stress
dia - gnost - ic (3 syllables)
Stress on 2nd syllable (gnost)
Word forms
Adjective
- Base: diagnostic
Noun
- Base: diagnostic
- Plural: diagnostics
Word family
Expressions
diagnostic code
1/dˌaɪəɡnˈɑstɪk kˈoʊd/
fixed phrase
technical
standard number showing diagnosis or error
A number or short group of letters and numbers that shows a specific medical diagnosis or technical error.
Examples
- The insurance form requires the correct diagnostic code for payment.
- A diagnostic code on the dashboard showed a problem with the fuel system.
- The technician read the diagnostic codes from the car's computer.
diagnostic criteria
1/dˌaɪəɡnˈɑstɪk kɹaɪtˈɪɹiə/
fixed phrase
technical
rules used to make a diagnosis
The official list of signs, symptoms, and rules that doctors use to say that someone has a certain disease or condition.
Examples
- The diagnostic criteria for the disorder were recently updated.
- He does not meet the diagnostic criteria for depression.
- Clear diagnostic criteria help doctors make consistent decisions.
diagnostic imaging
1/dˌaɪəɡnˈɑstɪk ˈɪmɪd͡ʒɪŋ/
fixed phrase
technical
medical scans to see inside body
Medical tests like X‑rays, CT scans, and MRIs that make pictures inside the body to help find disease or injury.
Examples
- She was sent to the diagnostic imaging department for a CT scan.
- Modern diagnostic imaging has greatly improved cancer detection.
- The clinic specializes in advanced diagnostic imaging techniques.
diagnostic test
1/dˌaɪəɡnˈɑstɪk tˈɛst/
fixed phrase
technical
test to find a disease or problem
A special test that helps doctors or experts find what disease, fault, or problem is present.
Examples
- The doctor ordered a diagnostic test to check for allergies.
- Many hospitals now offer same‑day results for basic diagnostic tests.
- This diagnostic test can detect the virus in its early stages.
diagnostic tool
1/dˌaɪəɡnˈɑstɪk tˈul/
fixed phrase
technical
device or method to find problems
A piece of equipment or a method that helps a person find the cause of a problem.
Examples
- Blood tests are an important diagnostic tool in modern medicine.
- This software is a powerful diagnostic tool for network administrators.
- X‑rays are commonly used as a diagnostic tool for broken bones.
run a diagnostic
1/ɹˈʌn ə dˌaɪəɡnˈɑstɪk/
fixed phrase
technical
perform a test on a system
To start and use a test program or tool to look for problems in a computer, car, or other machine.
Examples
- Let me run a diagnostic on your laptop to see what's wrong.
- The mechanic decided to run a diagnostic before replacing any parts.
- IT support asked me to run a diagnostic and send them the report.