Abbreviations: how confident are you?

ciAbbreviations are rife in medical texts. Some, such as DNA, are universally known and more common than their expanded forms. Others, such as CI (confidence interval) fall into a grey area. Widespread use of such abbreviations in English means they have been adopted in other languages too, particularly in the medical field. Out-of-English translators are then faced with a dilemma: should they translate commonly-understood English abbreviations or follow the practice of medical writers in their language and keep them in English?

Hyuna Ham* has been deliberating the pros and cons of translating well-known abbreviations out of English. She has written this guest post as a recapitulation and, above all, to hear your thoughts on the matter. Over to you, Hyuna.

95% CI: a de facto term?

Increased global use of English abbreviations means that, for example, everyone in the scientific world knows what “95% CI” means, in English-speaking and non-English-speaking countries alike. This is probably due to:

  • global cooperation in the science communities,
  • predominant use of English in the scientific literature,
  • education using English materials in many countries,
  • study or work abroad by scientists, and
  • possible generation-related attributes (younger professionals tend to use more English terms than the older). This is my opinion, based on my observations over the years.


I conducted a small informal survey in 18 countries among translators with whom I work. The responses revealed that:

  • the English abbreviation “CI” is commonly used and well understood in most countries,
  • older and more experienced translators always prefer the initialism of the translation of “confidence interval” in their languages if applicable, but they all acknowledge that “CI” is understood,
  • in many languages, the term “confidence interval” is one word (and therefore a two-letter abbreviation would have to be invented),
  • in some countries, the term is indeed two words but is never used in an abbreviated form.


Sometimes, a journal gives clear guidelines on abbreviations in its style guide or instructions to authors.1

A simple rule I usually apply to abbreviations I wish to keep in English is to translate the term in parenthesis/square brackets the first time it appears and use the English abbreviation alone thereafter. This particularly applies when the abbreviation is used or referred to multiple times throughout the document and also when it makes better sense to use it, for example, when space is restricted in a table.2

Besides the space-related limitation, another translation conundrum occurs when an abbreviation appears in tables or even in the text without glossing the term at all. To solve this, some translators decide to add a Translator Note to explain what the abbreviation stands for.

Over to you

I would appreciate your feedback on this issue. Specifically, I’d like to know:

  1. Do you use common English abbreviations in general, and CI in particular, in your out-of-English translations?
  2. How can we verify that an abbreviation in another language has reached the same level of usage as “CI” in English? Is Google sufficient to measure usage in particular countries?
  3. Stepping into my shoes as a project manager, would using “CI” for all countries (e.g., 95%CI) be justified for reasons of consistency?
  4. In which languages would “CI” be considered an error?

If, on the other hand, English is your target language, please let me know in the comments below how CI is dealt with in your source language texts.

I look forward to reading your comments below!

1 Abbreviations, Acronyms, and Initialisms, Emerging Infectious Diseases
2 AMA Manual of Style: A Guide for Authors and Editors (10th edition)


hyunaham* Hyuna Ham manages PA Translations, a specialized translation provider in New York, USA. She has a background and experience in immunology and IVD product development. She cherishes long-term collaboration with translators, many of whom have worked with her for the last 18 years!


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7 Responses to Abbreviations: how confident are you?

  1. Diana Rodríguez says:

    Hi, Emma and Hyuna. I’m from Colombia. Personally, I prefer to adapt abbreviations from English into Spanish if they exist because, why would you use a foreign word (or abbreviation) if you can use a word (or abbreviation) of your own language, especially when its use is common and totally natural? When translating “95% CI” into Spanish, I always change it to “IC de 95 %” or simply “IC 95 %”, and I do the same with all other applicable abbreviations. However, one must be always careful to avoid ‘making up’ abbreviations that actually don’t exist.

    Some common examples I find every day in my job (from English into Spanish):
    DNA = ADN
    RNA = ARN
    CI = IC
    IRB = CIR
    REC = CEI
    CRO = OIC
    HBV = VHB
    HCV = VHC
    HIV = VIH
    CRP = PCR
    AE = EA
    SAE = EAS
    ARD = RAM

    I should add that, unlike English, abbreviations in Spanish must not be pluralized (never add ‘s’!).

    • Christian Esquivel says:

      I agree with Diana 100%. I’m also a translator from Colombia and work mostly with the medical, pharmaceutical and legal fields. I always translate abbreviations, unless: 1. The clients specifically ask me not to do so; 2. There is no widely known equivalent abbreviation in Spanish, and the English acronym is the standard in Spanish as well. I also spell out the entire term if there is no equivalent abbreviation in Spanish and the abbreviation in English is not well known to Spanish speakers or when the document is intended for patients or the general public.

  2. Hi, this is Anabel from Spain. One of the main differences is that abbreviations in Spanish are not as usual as in English, and in Spain medical staff uses a lot of them in English because is how they know them. I suggest to check if possible with the National Association of the relevant disease; some of them have their own glosaries and the equivalence in other languages.

  3. Giovanna Maria Parisi says:

    Hi. Giovanna Maria from Italy. I usually do the same as you, translating the term in parenthesis and italic type the first time it appears and then using the English abbreviation. At the beginning, I had the same doubt, too, and I used to translate whenever I could find relevant references in italian documents. However, now the use of english abbreviations and terms is spreading in all types of publications so, unless differently indicated, I tend to leave them in english.
    Thank you for the opportunity to chat about our profession 🙂

  4. If anyone would like to read this blog post in Portuguese, Márcio Martins has translated it on his blog:

  5. EP says:

    FYI my CI for abbreviations does not have much of an I. Not in my DNA, I guess! <;-)

  6. Tuula S says:

    Hi Hyuna and Emma,
    In Finnish, the full translation of “95% CI” is “95 %:n luottamusväli”. There is a space in front of the % mark, there is the genitive ending “n” (preceded by a colon because of orthographic rules) after the number 95, and luottamusväli (confidence interval) is one compound word. If an abbreviation is needed, it is CI. There is no abbreviation based on the Finnish word. Often this is written as “95% CI” or “95 % CI” (which are not strictly speaking orthographically correct) or “95 %:n CI” also in Finnish because, as you say, everyone understands “CI”.

    However, because there are not prepositions like “of, at, in, on, from, to” in Finnish (endings are used instead) sometimes one has to add endings (e.g. CI:n, CI:t) . Sometimes it is clearer to write out the word than to use the abbreviation. Finnish is not an Indo-European language (instead, it is Uralic like Estonian and Hungarian) and thus has very different grammar and syntax rules than most of the other languages in Europe.

    I think you cannot use “95% CI” automatically in Finnish everywhere because 1) strictly speaking it is not orthographically correct, although many Finnish speakers might not care 2) depending on any prepositions or plural markers in the English text, some endings might be needed in Finnish and they can only be added by a native speaker who knows the orthographic rules (not all native speakers know the rules well enough).

    I happened to see this abbreviation in Swedish the other day, there seems to be the abbreviation KI, so the word is “konfidensinterval”. However, I don’t know whether they also use CI.

    I hope this was helpful.

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