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Are you someone who is confused by the use of articles?

Articles are something which cause lots of non-native speakers problems.

For many students this is simply because articles don’t exist in their language, which makes understanding their use difficult. Learning how to use articles like a native speaker can be challenging because lots of medical nouns follow rules for articles.

In the example above, ‘operation’ is a type of procedure. Procedures are countable and so they require an article.

Here are some examples of procedures which require articles:

  • blood test
  • stool sample
  • ultrasound
  • exam
  • investigation
  • CT scan
  • biopsy

Quiz: Test your knowledge!

Think of other procedures with similar endings to the nouns below. Note: Your answers are likely to be countable nouns.

Countable noun: Your answer:

Possible answers: lumpectomy/tracheostomy/colonoscopy/echocardiogram.

Exceptions to this rule:

As with many grammar rules in English, there are some important exceptions. Some medical procedures are uncountable. This example here is commonly used in medical writing:

Mr X requires surgery next week to remove his appendix.

Examples of uncountable medical procedures

An important tip for identifying uncountable medical procedures is to look carefully at the endings of these words. Take a look in the examples below.

Kidney dialysis  Mr X has kidney dialysis 3 times a week. 
Catheterisation  Post-operatively, Ms X underwent catheterisation. 
Rhinoplasty  Rhinoplasty was performed 3 days ago. 
Angiography  Mr X underwent angiography. 
Liposuction  Mr X had liposuction twice last year. 
Acupuncture   Mr X visited a Chinese medicine doctor for acupuncture.  
Breast screening   Ms X has had annual breast screening. 

Remember: Articles also do not need to be used with medical conditions.

Did you know?

ALL nouns ending in ‘therapy’ are uncountable. Examples of this are:

Physiotherapy  Mr X needs to commence physiotherapy. 
Chemotherapy  Mr X requires chemotherapy. 
Occupational therapy  Occupational therapy has been recommended. 

Turning uncountable nouns into countable nouns

Some nouns are confusing because if you change the ending slightly, they become countable:

Uncountable  Countable 
Breast screening A breast screen.
Angiography An angiogram.




What about plural nouns?

Articles can be omitted before plural nouns.


  • X-rays were carried out, which revealed a left pneumothorax.
  • Blood tests showed raised cholesterol levels.
  • The wound was cleaned, and dressings were re-applied daily.

Choosing the correct indefinite article

We know that ‘a’ or ‘an’ are used to describe a non-specific noun, which is general, and not known to the reader. 

Remember to think about how the noun sounds. Use ‘a’ before a consonant sound, and use an before a vowel sound. 


  • Mr X had an ultrasound.
  • Mr X requires a left knee replacement.

BewareSome nouns may start with a consonant, but still use an before them. This is because the SOUND of the word still begins with a vowel.  


  • Ms Jameson requires an X-ray. (pronunciation = an ex-ray)
  • Ms Jameson had an MRI today. (pronunciation = an em R I)

Quiz: Test your knowledge!

Try this QUIZ to test your understanding. Which of these sentences are correct, and which are incorrect? 

  1. Mr X has had a colostomy since 2018.
  2. Please remind Ms X that a breast screening is a free service for eligible patients
  3. She may benefit from a physiotherapy, to help her recover more quickly.
  4. Mr X has been advised that surgery is the best option to manage her condition.
  5. Mr X was admitted to hospital for the kidney dialysis on 4th September 2020.
  6. Angiogram revealed restricted blood flow to the heart.


  1. Correct.
  2. Incorrect.
  3. Incorrect.
  4. Correct.
  5. Incorrect.
  6. Incorrect