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Alphabetization and Sorting 

Alphabetization and Sorting
Medical Indexes

Bruce McGregor

and Harriet S. Meyer

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Alphabetization and Sorting

Alphabetization in indexes begins with the first letter of the term, eg,

G period

G phase

G protein

Commas precede letters in sorting order (examples from Thomas9).

cold, common

cold agglutinin disease

Vibrio, noncholera

Vibrio cholerae infection

Other punctuation is ignored.3

Omsk hemorrhagic fever virus

O'nyong-nyong virus

For entries that are identical except for case, choose whether uppercase or lowercase will take precedence in sorting and be consistent throughout the index.3

abl1, 99, 106–110

Abl1, 95, 100–103

Brca1, 112

BRCA1, 54, 804–809

When an identifier in parentheses is used to clarify similar terms, the identifier may be included in sorting (follow house style).

Abl1 (mouse gene), 95, 100–103

Abl1 (mouse protein), 98–99, 106

abl1 (retroviral oncogene), 99, 106–110

BRCA1 (human gene), 54, 804–809

Brca1 (mouse gene), 112

In biomedical indexes, numeric prefixes and chemical prefixes (eg, d-, l-, keto-, N-), are usually ignored for purposes of alphabetization and sorting of main entries (first set of examples adapted from Thomas9).




6-keto prostaglandin F, 119

13,14-dihydro-15-keto prostaglandin F, 120

prostaglandins, 98–112, 345–367

Note: A better arrangement of the latter set of entries might be as follows:

prostaglandins, 98–112, 345–367

 6-keto prostaglandin F, 119

 13,14-dihydro-15-keto prostaglandin F, 120

For terms with other prefixes, use cross-references or double-postings (see 13.2.4, Features of Indexes, Double-postings) if the text suggests that readers are likely to seek the term under the main portion of the keyword.

E-selectin. See under selectins

P-selectin. See under selectins

Terms with numbers appear in numerical order.







Numbers within terms are sorted ahead of letters, eg, CX3C precedes CXC.

chemokine subfamilies, 801–858

 CC, 250, 825–830

 CX3C, 764, 820–825

 CXC, 826–840

  CXCL1, 830–832

  CXCL4, 835–839

 XC, 841–855

Numbers that are parts of formal names are alphabetized as though written out,4 for instance, a study-group name in an author index:

Nilanont Y

903 Study Group

Nishiguchi S

For Greek letters, follow house style if specified.8 Greek letters are usually treated as though they were spelled out, eg, b is “beta,” g is “gamma.”

GABA (γ-amino butyric acid), 244, 350–366, 998

γ-amino butyric acid. See GABA

γ chain, 243. See also IgG

Alphanumeric combinations are sorted by letter (including Greek), then number (including subscripts).

α-adrenergic receptors

α2-adrenergic receptors

β-adrenergic receptors

β1-adrenergic receptors

In long series of Greek-letter–affixed terms that are likely to be listed together, alphabetizing according to the Greek letter and not its name spelled out in English is preferable.








Symbols are sorted as though written out. Consider using double-postings, a separate symbol index or group,7 cross-references, or a key to direct readers to symbol entries.

@ (“at”), in gene symbols, 495–497

χ2(chi-squared), 206

Formal binomial organism names (see 15.14, Nomenclature, Organisms and Pathogens) used as index entries are not separated5:

Staphylococcus albus

Staphylococcus aureus





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