Ambiguous prefixes

Prefixes are commonly used in medicine, but terms carrying opposite meaning often sound deceptively similar. Hypo- and hyper, ad- and ab, inter- and intra can be difficult to distinguish in everyday communication.

We suggest plain terms that clearly describe the clinical information.


Example: High potassium instead of hyperkalaemia



Not all acronyms have universally agreed meaning and often a single acronym can have different meanings. Depending on the context, MS can mean mitral stenosis or multiple sclerosis, or indeed morphine sulphate or millisecond. An ICD is an implantable cardiac defibrillator or an intercostal drain, but might also refer to the international classification of diseases.

Even more singularly defined acronyms can easily have their meaning distorted by typos or illegible handwriting. CRP easily becomes CPR. An entry in the patient’s notes stating “did not attend” (DNA) is substantially different from one saying “do not attempt resuscitation” (DNAR).

We suggest spelling out clinical terms in full, especially when the information conveyed has implications for patient care (as it often does).


Example: Mitral regurgitation instead of MR

Using numbers

Medical terminology tends to encourage binary states rather than a clinical spectrum. Even when we stick to unambiguous terminology, the clinical implications of “high potassium” can be vastly different depending on whether “high” means a potassium concentration of 5.6 or 7 for example. Pre-fixing clinical problems with relevant numbers makes it easy to prioritise them clinically and give a fuller picture.


Example: Low blood pressure 80 mmHg systolic instead of hypotension

Insulin names

There is an ever-growing number of insulins, which can cause confusion among patients and healthcare staff. Pre-mixed insulins usually have a number affixed, denoting the ratio of short- to long acting insulin they contain, e.g. NovoMix 30.  There is potential for this number to be confused with the dose of insulin to be administered, especially of they are written together.

We propose clearly denoting insulins as such to keep communication as unambiguous as possible.


Example: HumalogMix 25 insulin 25 units instead of HumalogMix 25 25 units

Right and left, correct and incorrect

Relative anatomical directions are often necessary in medicine, but can be confused, with potentially disastrous consequences. In light of this, we propose that right and left are always written as such in the notes, and not abbreviated R and L respectively. Further confusion can arise from the double meaning of right as both a relative direction as well as an affirmative. We therefore suggest that in clinical communication correct/incorrect are used instead of right/wrong.

Example: "The left neck of femur is fractured?" "That is correct"

Signposting life threatening reactions

Systems designed to alert healthcare staff to severe allergies are often used liberally to include intolerances or minor reactions. Signposting life threatening reactions such as anaphylaxis unambiguously increases vigilance and can prevent errors.

Example: Life threatening reaction to penicillin instead of Allergic to penicillin

© 2017 by Hans van Huellen