Expressions of concentration in nonmetric units
When expressing concentrations of nonmetric units of measure, spell out the word per and do not use a virgule. A virgule implies an abbreviated expression and nonmetric units are not abbreviated.
The patient's heart rate was 110 beats per minute.
We will prescribe Valium 5 mg per day.
She will take the prescribed dose 3 days per week.
EXCEPTION: Use a virgule when the expression combines a metric unit with a nonmetric unit.
The IV was set to run at 10 mcg/min.
The SI style for reporting molar solutions is mol/L (1 g by molecular weight in 1 L of solution). For solutions with milliimolar concentrations, mmol/L is used. For solutions with micromolar concentrations, the convention is to use µmol/L.
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