Error-Prone Symbols

ERROR-PRONE SYMBOLS
The symbols found in this table have been reported to the Institute for Safe Medical Practices (ISMP) through the ISMP Medication Error Reporting Program as being frequently misinterpreted and involved in harmful medication errors. These symbols should never be used when communicating medical information.
Symbol	Intended Meaning	Misinterpretation	Correction
ʒ	Dram	Mistaken as “3”	Use the metric system
♍	Minim	Mistaken as “mL”	Use the metric system
x3d	For three days	Mistaken as “3 doses”	Use “for three days”
> and <	Greater than and less than	Mistaken as opposite of intended; incorrect symbol used mistakenly; “<10” mistaken as “40” (forty)	Use “greater than” or “less than”
/ (slash mark)	Separates two doses or indicates “per”	Mistaken as the number 1 (eg, “25 units/10units” misread as “25 units and 110 units”)	Use “per” rather than a slash mark to separate doses
@	At	Mistaken as “2”	Use “at”
&	And	Mistaken as “2”	Use “and”
+	Plus or and	Mistaken as “4”	Use “and”
°	Hour	Mistaken as a zero (eg, q2° seen as q 20)	Use “hr”, “h”, or “hour”
Φ or ∅	Zero, null sign	Mistaken as numerals 4, 6, 8, and 9	Use 0 or zero, or describe intent using whole words
REFERENCES
Source: Institute for Safe Medication Practices. Error-Prone Abbreviations, Symbols, and Dose Designations. 2015. Available at: http://www.ismp.org/Tools/ errorproneabbreviations.pdf. (Rev. 5/2018)

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