John Dixon, independent medical writer and trainer in scientific writing skills, provides a useful tip for medical writers who work in MedComms.

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Recorded 25 March 2019. Produced by

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Hi, I’m John Dixon, a trainer in scientific writing, and here’s a bite that I hope may help you with your writing.

Using abbreviations and acronyms [NEXT SLIDE]

An abbreviation is a single letter or series of letters used as a shortened form of a word or phrase; the individual letters are often pronounced:
so – DNA, NMR, e.g.
An acronym is a type of abbreviation in which the letters form a pronounceable word:
so – CONSORT, PET, laser, scuba [NEXT SLIDE]

Abbreviations should be used: ‘to save space and time, to avoid repetition of long words and phrases, or…to conform to conventional usage.’]
So, don’t you just hate this sort of statement: ‘PDQ was used to compare the OP of ABC and XYZ at D3 in CF.’ [NEXT SLIDE]

Some abbreviations don’t need to be defined such as
SI and SI-derived units …pause… ‘s’ for seconds, ‘min’ for minutes, and so on …. and …
You don’t need to define well-known abbreviations that are widely known or certainly widely used within a discipline – for example DNA and e.g. – both widely known – and CABG – well known by healthcare professionals [NEXT SLIDE]

So, define an abbreviation at first use – write the full expression followed by the abbreviation in parentheses
Human chorionic gonadotrophin – and in parentheses HCG – is produced by the placenta during pregnancy.
Be careful not to define using a plural in the definition, and then give the singular of the abbreviation.
So it’s incorrect to write – People go to general practitioners (GP) for medical advice.
Correctly written, it would be better to write – People go to a general practitioner (GP) for medical advice. [NEXT SLIDE]

Here are some tips about when to abbreviate, and when not to abbreviate.
The Chicago Manual of Style suggests using abbreviations if they’re to be used around 5 or more times in an article. It’s not helpful to define and introduce an abbreviation if the abbreviation is never – or rarely to be used again in the document.
Don’t use abbreviations for shorter words or phrases
If defined in the abstract, redefine the abbreviation in the article body
Avoid abbreviations that can cause confusion or ambiguity – for instance NAD can be used to mean ‘no abnormality detected’ or ‘nicotinamide adenine dinucleotide’
Self-invented abbreviations can be useful for complex terms used frequently, but do define them on first use [NEXT SLIDE]

Finally, refer to a style guide whenever possible to ensure you use abbreviations correctly – and be consistent throughout a document … here are some of the style guides I use.

I hope that’s helpful. For more bites to help your writing, visit

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[For the avoidance of doubt: this video is intended to be freely accessible to all. Please feel free to share and use however you like. Cheers Peter Llewellyn, Director NetworkPharma Ltd and Founder of the MedComms Networking Community activity at]