OET Writing · Updated 2026
OET abbreviations: what case-note shorthand means and how to write it in your letter
OET case notes are written in medical shorthand: t.d.s., 3/7, NBM, c/o, ?DVT. Your letter has to be written in full sentences that any reader can follow. Here are 20 of the abbreviations you will meet most, each with a line from the case notes and how to write it in your letter.
The rule
Write out every piece of case-note shorthand. Keep units of measurement (mg, mL, mmol/L, mmHg) and the few terms every clinician reads as a word, such as GP, ECG, CT and BMI. Leaving shorthand in the letter costs marks under Genre and Style and under Conciseness and Clarity, because the reader may not share your local conventions.
20 abbreviations with letter examples
- 01
t.i.d. / tds
three times a dayAlso written: tid, t.d.s.
Case notes
Amoxicillin 500mg tds x 7/7
In your letter
She was prescribed amoxicillin 500 mg three times a day for seven days.
- 02
b.i.d. / bd
twice a dayAlso written: bid, b.d.
Case notes
Metformin 500mg b.i.d.
In your letter
He takes metformin 500 mg twice daily.
- 03
prn
when neededAlso written: p.r.n.
Case notes
Salbutamol inhaler prn
In your letter
She uses a salbutamol inhaler when required.
- 04
nocte
at nightCase notes
Simvastatin 20mg nocte
In your letter
He takes simvastatin 20 mg at night.
- 05
stat
immediately, as a single doseCase notes
Ceftriaxone 2g IV stat
In your letter
A single dose of intravenous ceftriaxone 2 g was given immediately.
- 06
x/7
number of days (3/7 = three days)Case notes
Fever 3/7
In your letter
She has had a fever for three days.
- 07
x/52
number of weeks (2/52 = two weeks)Case notes
Review in 2/52
In your letter
I will review him in two weeks.
- 08
NBM
nil by mouth (nothing to eat or drink)Also written: NPO
Case notes
NBM from midnight
In your letter
She should have nothing to eat or drink from midnight.
- 09
PO
by mouth (oral)Case notes
Prednisolone 40mg PO
In your letter
She was started on oral prednisolone 40 mg.
- 10
SC
subcutaneous (under the skin)Also written: s/c, subcut
Case notes
Enoxaparin 40mg SC od
In your letter
She is on enoxaparin 40 mg by subcutaneous injection once daily.
- 11
SOB
shortness of breathAlso written: SOBOE = short of breath on exertion
Case notes
SOB on exertion
In your letter
She becomes short of breath on exertion.
- 12
N&V
nausea and vomitingAlso written: N/V
Case notes
N&V x 2/7
In your letter
He has had nausea and vomiting for two days.
- 13
HTN
hypertension (high blood pressure)Case notes
PMHx: HTN, NIDDM
In your letter
His medical history includes hypertension and type 2 diabetes.
- 14
NKDA
no known drug allergiesCase notes
Allergies: NKDA
In your letter
He has no known drug allergies.
- 15
c/o
complains ofCase notes
c/o chest pain
In your letter
He reports chest pain.
- 16
Hx
historyAlso written: PMHx = past medical history, FHx = family history
Case notes
PMHx: asthma
In your letter
She has a history of asthma.
- 17
O/E
on examinationCase notes
O/E: chest clear
In your letter
On examination, her chest was clear.
- 18
NAD
nothing abnormal detectedCase notes
Abdo – NAD
In your letter
Abdominal examination was unremarkable.
- 19
?
possible, suspectedCase notes
?appendicitis
In your letter
Appendicitis is suspected.
- 20
#
fractureCase notes
# NoF
In your letter
She sustained a fracture of the neck of the femur.
The rest are in OETgo
Study the full list of case-note abbreviations and symbols as flashcards, each with a case-note line and how to write it in your letter. The ones you miss come back for review. Included in the Standard, Intensive and Unlimited plans.
Create free accountThree traps when writing them out
Numbers over 7, 52 and 12 are durations
3/7 is three days, 2/52 two weeks, 6/12 six months. Reading 3/7 as the 3rd of July puts a wrong date in your letter and costs Content marks.
? means suspected, not confirmed
“?DVT” means a DVT is suspected. Write “a deep vein thrombosis is suspected”, not “she has a deep vein thrombosis”. Dropping the doubt changes the clinical picture.
Expanding is not enough, rewrite the sentence
“N&V x 2/7” written out word for word is still note form. Turn it into prose: “He has had nausea and vomiting for two days.”
Frequently asked questions
What does NBM mean in OET case notes?
Nil by mouth: the patient should have nothing to eat or drink. In your letter write, for example, “She should have nothing to eat or drink from midnight.”
What does prn mean?
When needed (from the Latin pro re nata). “Salbutamol inhaler prn” becomes “She uses a salbutamol inhaler when required.”
What does c/o mean in medical notes?
Complains of. “c/o chest pain” becomes “He reports chest pain.” or “He complains of chest pain.”
Can I use abbreviations in my OET letter?
Keep units of measurement (mg, mL, mmol/L) and a few terms every clinician reads as words, such as GP, ECG and CT. Write everything else out. Case-note shorthand like SOB, N&V, 3/7 or c/o belongs in the notes, not the letter.
What does 3/7 mean in OET case notes?
Three days. The number over 7 counts days, over 52 counts weeks and over 12 counts months, so 2/52 is two weeks and 6/12 is six months. It is a duration, not a date.
Is it t.d.s. or t.i.d.?
Both mean three times a day. OET case notes use either form, as do b.d./b.i.d. (twice a day) and q.d.s./q.i.d. (four times a day). In your letter, write the plain English: three times a day.
How many abbreviations do I need to know for OET?
There is no official list, but the same ones come up again and again. OETgo covers the OET Teachers Handbook list plus the shorthand found in OET sample case notes.