Expressing numbers as a percentage
Percentages are used to express a ratio or fraction that means "per one hundred."
Abbreviated
Percent is a single word and should not be written as two words (i.e., per cent). Do not abbreviate (pct.) except in tables.
The appropriate abbreviation for medical records is the percent sign (%). Use the symbol % after the numeral. Do not space between the numeral and the symbol.
Blood showed 12% monos and 1% bands.
There was a 12% increase in size since the tumor was last evaluated.
A 10% solution was applied.
Always use a numeral for the number preceding the % symbol; do not spell out the number.
There was a reduction of 50%
not
There was a reduction of fifty %
not
There was a reduction of fifty percent.
Spelled out
It is sometimes necessary to spell out a number when it begins a sentence. If the sentence cannot be recast and the number is expressing a percentage, then the percentage symbol is not used. Both the number and the word percent are written out.
Fifty percent of patients returned for a followup study.
Percentages in ranges
When percentages are expressed in ranges of values, repeat the % symbol for each quantity expressed.
Fluctuations in size ranged from 3% to 10%
not
Fluctuations in size ranged from 3 to 10%
not
Fluctuations in size ranged from 3-10%
Percentages spelled out in ranges
The same rules apply as for spelling out percentages. If a percentage value occurs at the beginning of a sentence which cannot be recast, the value that begins the sentence must be spelled out; the range values can be expressed numerically.
Fifty percent to 80% of the study respondents...
Percentages less than 1
When a percentage amount is less than 1 (i.e., a fraction of 1%), place a zero before the decimal for clarity.
The patient was injected with 0.5% Marcaine
NOT
The patient was injected with .5% Marcaine
Whole numbers and zero
With whole numbers, do not follow the number by a decimal point and a zero unless dictated. However, avoid whenever possible, as this could be misread.
There was a 5% variance
NOT
There was a 5.0% variance
Fractional decimal values
Percentages are always expressed using decimals, never fractions, even if dictated as a fraction. If dictated, convert to the appropriate decimal.
D: A solution of half-percent Marcaine was used.
T: A solution of 0.5% Marcaine was used.
NOT
A solution of 1/2% Marcaine was used
NOT
A solution of 1/2 percent Marcaine was used
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