OET Writing Grammar: The 8 Errors That Most Often Cost Language Marks

Grammar errors in OET writing are rarely caused by not knowing English — most candidates at B2 level and above know the rules. The errors are caused by not noticing the error in a letter you have just written, under time pressure, in a clinical register that is not your daily English. This guide covers the eight patterns that most often appear in letters that fall short of the Language mark, with before/after examples and a check you can run in under two minutes.

For the full framework: OET writing criteria and the proofreading routine.

The 8 grammar errors in ranked order

Error 1: Articles

The article system is the hardest area of English for speakers of languages without articles (Arabic, Filipino, Chinese). The clinical rule differs from everyday English:

• No article for diagnoses: “She has hypertension” not “She has the hypertension”
• Definite article for shared-reference nouns: “the patient”, “the referral”, “the specialist”
• Indefinite article for first-reference countable nouns: “a 52-year-old male”, “a new fracture”

Scan every noun in your letter during proofreading and ask: is this a diagnosis (no article), something both reader and I can identify (the), or first reference to a countable thing (a/an)?

Error 2: Tense inconsistency

Wrong: Mr Al-Farsi was admitted last month. He has a history of hypertension. His blood pressure was 160/100. He is currently recovering well.
Correct: Mr Al-Farsi was admitted last month. He has a longstanding history of hypertension. His blood pressure on admission was 160/100 and has since stabilised. He is currently recovering well.

The pattern: events that happened and finished → past simple. Recent events with current relevance → present perfect. Ongoing facts that are still true → present simple.

Error 3: Subject-verb agreement in long noun phrases

The verb agrees with the head noun, not the most recent noun:

Wrong: The dose of the two antihypertensive medications were adjusted.
Correct: The dose of the two antihypertensive medications was adjusted. (Subject = “dose”)

Wrong: His results, including the ECG and the blood tests, was reviewed. (Correct: were reviewed. Subject = “results”)

Error 4: Prepositions after clinical verbs

These are fixed collocations — there is no rule to derive them, only patterns to memorise:

• Referred to (a doctor) / referred for (a procedure) — “referred to the cardiologist for review”
• Commenced on (a drug) — “commenced on metformin 500 mg”
• Admitted to (a ward) — “admitted to the medical ward”
• Discharged from (hospital) — “discharged from the Royal Hospital”
• Compliant with (medication) — “compliant with her current regimen”

Errors 5–8: Quick checks

Comma splice: if you join two full sentences with a comma, use a full stop or a conjunction. “The results were abnormal, the patient was admitted” → “The results were abnormal, so the patient was admitted.”

Relative clause punctuation: “Mr Hassan, who is 54, was admitted” (non-restrictive: commas required). “The patient who developed the rash was reviewed” (restrictive: no commas).

Run-on sentences: if a sentence has more than two verbs, count the conjunctions. If there are none, split the sentence at a logical point.

Over-passive: “It is recommended that a review be conducted” → “I would be grateful if you could review”. The second is warmer, clearer, and the OET-preferred register for requests.

Grammar check in two minutes

During your proofreading routine, make one backward pass (last sentence to first) checking:

1. Every noun — correct article?
2. Every verb — correct tense?
3. Every sentence junction — full stop or conjunction, not a comma?

For a detailed Grammar analysis against the OET criteria, use the free Grammar Checker or submit a letter for professional correction with criterion-by-criterion feedback.