AMA Manual of Style - Stacy L. Christiansen, Cheryl Iverson 2020
Forward Slash (Virgule, Solidus)
The forward slash is used to represent per, and, or or and to divide material (eg, numerator and denominator in fractions; month, day, and year in dates [only in tables and figures]; lines of poetry). It may also be used in URLs (see 2.0, Manuscript Preparation for Submission and Publication).
8.4.1 Used to Express Equivalence or Duality.
When 2 terms are of equal weight in an expression and and is implied between them to express this equivalence, the forward slash can be retained.
Developing skin cancer screening recommendations in the Hispanic/Latino population can be challenging.
The diagnosis and initial treatment/diagnostic planning were recorded.
There was an excess incidence of prostate cancer, thyroid cancer, and multiple myeloma in the rescue/recovery workers.
This is an and/or decision.
If the approval process raises concerns among the researchers or the ethics committee/institutional review board members, the author may want to explain the resolution of these issues.
When the question of duality arises in the he/she construction, change the slash construction when the sex or gender is to be specified; substitute the word or for the forward slash or, preferably, rephrase to be gender neutral.
Dr Kate Wolf and Dr Rob Cox agreed to serve on the nomenclature committee. Now I need to know whether he or she [not he/she] will lead the subcommittee on genetic nomenclature.
Better: Now I need to know which of them will lead the subcommittee.
If the sex is unspecified and does not matter, the slash construction is permissible.
This aspiration technique is one that any physician can master whether or not he/she has surgical expertise.
See also 18.104.22.168, Pronoun-Pronoun Agreement, regarding use of they as a singular pronoun when rewriting would be awkward or unclear.
Note: The trend is toward rephrasing such sentences and using the plural to avoid sexist language; eg, “This aspiration technique can be mastered by physicians whether or not they have surgical expertise.” (See 11.12, Inclusive Language.)
Although the forward slash can be used to indicate alternative or combined states in the same person, such as Jekyll/Hyde personality, it is important that no ambiguity be present. If there is any likelihood of ambiguity, the sentence should be reworded or rephrased for clarity:
The study found that 86 (4.5%) were both perpetrators and survivors (originally “perpetrators/survivors”).
8.4.2 Used to Mean per.
In the “per” construction, use a forward slash only when (1) the construction involves units of measure (including time) and (2) at least 1 element includes a specific numerical quantity and (3) the element immediately adjacent on each side is either a specific numerical quantity or a unit of measure. In such cases, the units of measure should be abbreviated in accordance with 13.12, Units of Measure (see 18.7.3, Reporting Proportions and Percentages).
The hemoglobin level was 14 g/dL.
The CD4+ cell count was 200/μL.
Blood volume was 80 mL/kg of body weight.
Respirations were 60/min; pulse rate was 98/min.
The drug dosage was 30 mg/d.
Annual screening in the reference group had an incremental cost-effectiveness of CaD $24 000 per quality-adjusted life-year (QALY); adding a smoking cessation program to screening could lower the incremental cost-effectiveness to CaD $52 000/QALY.
Do not use the forward slash in a “per” construction (1) when a prepositional phrase intervenes between the 2 units of measure, (2) when no specific numerical quantity is expressed, or (3) in nontechnical expressions.
4.5 mEq of potassium per liter
(Avoid: 4.5 mEq/L of potassium; instead reword: a potassium concentration of 4.5 mEq/L.)
expressed in milliliters per minute
2 days per year
An exception is often made in table footnotes to save space:
Cholesterol is expressed as mg/dL.
See also Table 4.1-10.
8.4.3 In Dates.
Use the forward slash in dates only in tables and figures to save space (month/day/year) (see 4.1.6, Tables, Punctuation). Avoid this presentation of dates in the text.
8.4.4 In Equations.
In equations that are set on the line and run into the text rather than centered and set off (see 20.2, Stacked vs Unstacked Fractions or Formulas), use the forward slash to separate numerator and denominator.
The stacked fraction is written as y = (r1+r2)/(p1—p2) in this equation.
Note that when the slash is used for this purpose, parentheses and brackets must often be added to avoid ambiguity.
Although a forward slash may be used to express a ratio (eg, the male/female [M/F] ratio was 2/1), the JAMA Network journals recommend use of a colon to express ratios that involve numbers or abbreviations (the Apo B:Apo A-I ratio was 2:1) and the word to to express ratios involving words (the male to female ratio) (see 22.214.171.124, Colon, Numbers).
8.4.6 Phonetics, Poetry.
The forward slash is also used to set off phonemes and phonemic transcription and to divide run-in lines of poetry.
/d/ as in dog
. . . cold-breath’d earth!/Earth of the slumbering and liquid trees!/Earth of departed sunset─/Earth of the mountains misty-topt!