Hyphenating letter-number-symbol combinations
Some terms with a single letter or symbol followed by a word are hyphenated. Consult an accepted medical or English language dictionary if uncertain; consider the hyphen optional if you are unable to find a reference source to document. Some examples follow.
B-complex vitamins
B-cell helper
Z-plasty
T-cell marker
T cell
prostate-specific antigen
graft-vs-host disease
B cell
Do not hyphenate modifiers in which a letter or number is the second element.
grade AA eggs
type 1 diabetes mellitus
Use a hyphen to form a compound modifier between a number and a word if it precedes and modifies a noun. When the word represents a unit of measure, hyphenate only when the unit is an English unit of measure. Do not hyphenate compound modifiers if the unit of measure is an abbreviated metric unit, where neither element (the unit of measure nor the metric measurement) forms an actual word. (See NOTE below.)
The patient had a 2-week history of cough and sore throat.
The patient is a 58-year-old female.
She delivered a 7-pound 10-ounce baby boy
We sutured a 2-inch laceration
versus
We made a 3 cm incision
A 1 mg injection was given
The patient had a 1 x 2 x 1 cm contusion
NOTE: There is some confusion between this recommendation from the AHDI Book of Style and the guidelines contained in the AMA Style Guide, which does not note this exception; and in fact, gives examples contrary to this guideline. Please check with your client, account manager and/or QA for guidance.
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