14 Science, mathematics, and computing

14.3 Medical terminology

14.3.1 Abbreviations

Abbreviations should be defined when first used. Avoid using clinical-style shorthand in formal writing (US for ultrasound; Hb for haemoglobin unless referring to specific types; see 14.3.3).

Abbreviations of Latin terms are now discouraged, particularly in pharmacology, where clarity of meaning is paramount. In addition, British and US usage differs in some cases (see Table 14.2).

The same abbreviations may be used for different terms: CSF may be cerebrospinal fluid or colony-stimulating factor. Which of these abbreviations should be employed in a text depends on the type of work and its expected readership.

Some abbreviations will be so familiar to the readership that they do not need to be defined (DNA, HIV) but be aware that some well-known English abbreviations may be known by a different abbreviation in other languages (AIDS, SIDA in French). It is useful to have a house style list of those that do not need to be defined for a particular specialty but, if in doubt, it is best to define it at some point.

Table 14.2 Dosage abbreviations




ante cibum (before food)



bis die (twice daily)



omni die (every day)


omni mane (every morning)



omni nocte (every night)


post cibum (after food)


pro re nata (when required)



quater die sumendum (to be taken four times daily)


quarta quaque hora (every four hours)


statim (immediately)



ter die sumendum (to be taken three times daily)


ter in die (three times daily)

14.3.2 Blood groups

Blood-group antigens are designated by capital letters, sometimes combined with a lower-case letter or letters, such as A, B, AB, O, Rh. Note that while A, for example, is defined as a blood group, not blood type, blood is described as being type A, not group A.

14.3.3 Haemoglobin

The types of normal human haemoglobin are designated Hb A, Hb A2, and Hb F. Their component globin chains are designated by a Greek letter (α, β, γ, or δ); subscript numerals indicate the number of chains. Abnormal haemoglobins are designated either by letters (C–Q, S) or by the name of the place where they were first identified (e.g. Hb Bart’s, Hb Chad).

14.3.4 Vitamins

The group of organic compounds that form vitamins may be known by their chemical names or by a single capital letter; those forming part of a group are identified further by subscript Arabic figures (e.g. vitamin B1). (Dietary minerals are known only by their chemical names.)

14.3.5 Immunology

Symbols for human histocompatibility leukocyte antigens are HLA followed by a letter to designate the class (e.g. HLA-A). Classification is complex and ongoing; consult the website of the World Health Organization Nomenclature Committee for Factors of the HLA System, which changed the way HLA alleles are designated and named in 2010. Symbols for human immunoglobulins are Ig also followed by a class letter (e.g. IgA); do not use Ig as an abbreviation for immunoglobulin. T cell is not hyphenated unless used adjectivally (T-cell receptor). The gene symbols for immunoglobulins and T-cell receptors are assigned by the ImMunoGeneTics (IMGT) Nomenclature Committee; lists of human and murine gene names can be found on their website. Symbols for many other molecules such as interferons consist of capital letters to designate the molecule, prefixed by the source, and followed by other designations (rhIFN-α1, recombinant human interferon-α1).

14.3.6 Diseases

Disease names may be descriptive or eponymic (e.g. Parkinson’s disease). Derived words do not take a capital letter (e.g. parkinsonism). See also 14.1.7 on eponymic designations. Note that descriptive names are now preferred (reactive arthritis over Reiter’s disease). Avoid using nouns derived from disease names to describe patients (diabetics, epileptics); use people with diabetes or epileptic patients for example.

14.3.7 Drug nomenclature

In professional or technical contexts, prefer a drug’s generic name (in lower case) to its proprietary name (with an initial capital), which may differ over time and between countries. Even generic names can vary, however, and there are several conventions worldwide, chiefly British Approved Names (BANs), Recommended International Non-Proprietary Name (rINNs), US Adopted Names (USANs), and Japanese Approved Names (JANs). European legislation requires the use of rINNs for medicinal product labelling and in 2003 all British Approved Names (BANs) were harmonized with rINNs with the exception of adrenaline (in rINN epinephrine) and noradrenaline (norepinephrine). Publishers should therefore impose rINNs/new BANs as a matter of policy. In a historical context, and for lidocaine (lignocaine) where changeover has been slower, it may be useful to add the original BAN as a gloss. The British National Formulary retains original BANs as synonyms and the Medicines and Healthcare Products Regulatory Agency (MHRA) website has a complete list of the BANs changed. A dictionary that includes all the international systems is published annually by the US Pharmacopeial Convention.

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