How to use acronyms

Last revised by Calum Worsley on 22 Nov 2021

Acronyms are abbreviations formed by the first letters or components of a word or phrase. They make life easier as a long term can be condensed into a short term that's easier to pronounce and write. No one likes to say or write "cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy", but it's no problem to say "CADASIL". Similarly, there are a number of commonly used non-medical abbreviations (e.g., i.e., etc.) that one can assume all readers are familiar with (see accepted abbreviations).

Unfortunately, in recent times there has been a tendency to attempt to reduce any and all repeated terms to TLAs (three letter acronyms), and medicine has been particularly afflicted. They are known to reduce comprehension, particularly when they are novel/not generally accepted, and so make it harder for individuals to understand the content when not reading from the very start. 

In the setting of, therefore, acronyms should generally be avoided except in specific situations where they are very well recognized. 

If one were being pedantic, then actually most medical acronyms in English are initialisms, as they are pronounced as individual letters rather than a word (e.g. AMI is said "a-em-eye" and not "aimee"). NASA is an example of a true acronym as it is pronounced as a word "nasa" rather than "en-a-es-a". All that having been said, most folks are now using the term acronym for both, and if you are reading this you are probably not getting invited to many parties anyway, so best to let it go. 

It can be tempting to abbreviate longer terms for repeated use in the remaining text ("convenience acronyms"). This practice is widely used in medical textbooks and journal articles, stemming in large part, from word count and page number limits. Unfortunately, acronyms reduce readability and comprehension, particularly when they are unfamiliar. Thus, since we don't need to worry about word length and readers often skip down to the middle of an article, we only use abbreviations or acronyms if they are widely known and used.

If an acronym is thought to be necessary (see above), the first time in a text it should be written in full with the acronym in parentheses. From there on the abbreviation/acronym can be used throughout.

When introducing the acronym/abbreviation it should be immediately after the abbreviated term, not at the end of a longer phrase that includes non-abbreviated parts, e.g.:

  • Cytomegalovirus (CMV) encephalitis is one of the more common opportunistic infections in patients with HIV
    > encephalitis is not abbreviated, so "(CMV)" ends up in the middle of the term

Acronyms are written with the individual (usually capital) letters forming a word, without full stops (periods) separating the letters, e.g. CMV, and not C.M.V.

  • the key exception to this, is for a few accepted abbreviations in which we stipulate that full stops are used, for example "e.g." (not eg), etc.

Acronym use in article titles

Whether to include an acronym in the title will depend on the degree of acceptance and use of the acronym. The acronym should be in the title only when in practice the acronym is the preferred term and the full term is hardly ever used. See article title for further information.

When using an acronym in a sentence, and needing to make the term plural, then an 's' should be appended to the acronym, without an apostrophe (read more about use of apostrophes).

In other words: 

  • correct: AMIs, MCAs, ELSTs
  • incorrect: AMI's, MCA's, ELST's

If the acronym ends with an S, the same rule applies: 

  • correct: SOSs
  • incorrect: SOS's, SOSes

In the rare circumstances where a standalone letter is pluralised then this rule still applies:

  • correct: Ss, Os
  • incorrect: S's, O's

Note: This is a topic of some contention and various style guides adopt different conventions. Please don't get upset by this. We have chosen this one as a common and simple option. 

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