Microgram: Difference between revisions
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In the [[metric system]], a '''microgram''' or '''microgramme''' is a [[Physical unit|unit]] of [[mass]] equal to one millionth ({{val|1|e=-6}}) of a [[gram]]. The | In the [[metric system]], a '''microgram''' or '''microgramme''' is a [[Physical unit|unit]] of [[mass]] equal to one millionth ({{val|1|e=-6}}) of a [[gram]]. Two different abbreviations are commonly used. The [[International System of Units]] (SI) uses '''μg''', where the [[Metric prefix|SI prefix]] "[[micro-]]" is represented by the Greek letter [[Mu (letter)|μ]] (mu). The abbreviation '''mcg''' is preferred for medical information in the United States (US), but prescription writing guidance in the United Kingdom advises that "microgram" should not be abbreviated.<ref>{{cite web |title=Prescription writing |url=https://bnf.nice.org.uk/medicines-guidance/prescription-writing/ |website=BNF |publisher=National Institute for Health and Care Excellence |access-date=9 November 2025}}</ref> A third abbreviation, the Greek letter '''[[γ]]''' (gamma), is no longer recommended.<ref>[https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-133 NIST Handbook 133 - 2018], [https://www.nist.gov/sites/default/files/documents/2017/04/28/12-apde-gentab-11-hb133-final.pdf#page=17 Appendix E. General Tables of Units of Measurement, page 159 (17)]</ref> | ||
The US [[Institute for Safe Medication Practices]] (ISMP) and the US [[Food and Drug Administration]] (FDA) recommend that mcg should be used, rather than μg, when communicating medical information.<ref>{{cite web |title=ISMP's List of Error-Prone Abbreviations, Symbols, and Dose Designations |url=https://www.ismp.org/recommendations/error-prone-abbreviations-list |access-date=2018-03-28 |publisher=ISMP}}</ref> This is due to the risk that [[micro-|μ]] might be misread as [[milli-|m]], for "[[milli-]]", which is equal to one thousandth ({{val|1|e=-3}}). Such a misreading could result in a thousandfold [[Drug overdose|overdose]] of a drug or medicine. However, mcg is also the symbol for the obsolete unit millicentigram, derived from the [[CGS|centimetre–gram–second system of units]] and equal to 10 μg. | |||
== | == Typography == | ||
Usually, a sequence of the [[Unicode]] code point {{unichar|03BC|}} followed by the Latin letter {{unichar|0067|}} should be used. However, if μ is not available it [[Micro-#Symbol encoding in character sets|may be represented]] with {{unichar|0075}} or the legacy Unicode symbol {{unichar|00B5|Square Mu G}}. In [[CJK characters|Chinese, Japanese and Korean]] writing a [[fullwidth]] version {{unichar|338D|Square Mu G}} should be used.<ref name="Unicode-U3300">{{cite web |url=https://www.unicode.org/charts/PDF/U3300.pdf |access-date=May 24, 2019 |title=The Unicode Standard 12.0 – CJK Compatibility ❰ Range: 3300—33FF ❱ |author=Unicode Consortium |author-link=Unicode Consortium |date=2019 |website=Unicode.org}}</ref> | |||
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==See also== | ==See also== | ||
{{wiktionary|microgram|μg|mcg}} | {{wiktionary|microgram|μg|mcg}} | ||
* [[Metric prefix#List of SI prefixes|List of SI prefixes]] | * [[Metric prefix#List of SI prefixes|List of SI prefixes]] | ||
* [[Orders of magnitude (mass)#10−12 to 10−6 kg|Orders of magnitude (mass)]], listing a few items that have a mass of around 1 μg. | * [[Orders of magnitude (mass)#10−12 to 10−6 kg|Orders of magnitude (mass)]], listing a few items that have a mass of around 1 μg. | ||
==References== | ==References== | ||
Latest revision as of 17:38, 9 November 2025
Template:Short description Script error: No such module "Hatnote". Template:Infobox unit In the metric system, a microgram or microgramme is a unit of mass equal to one millionth (Script error: No such module "val".) of a gram. Two different abbreviations are commonly used. The International System of Units (SI) uses μg, where the SI prefix "micro-" is represented by the Greek letter μ (mu). The abbreviation mcg is preferred for medical information in the United States (US), but prescription writing guidance in the United Kingdom advises that "microgram" should not be abbreviated.[1] A third abbreviation, the Greek letter γ (gamma), is no longer recommended.[2] The US Institute for Safe Medication Practices (ISMP) and the US Food and Drug Administration (FDA) recommend that mcg should be used, rather than μg, when communicating medical information.[3] This is due to the risk that μ might be misread as m, for "milli-", which is equal to one thousandth (Script error: No such module "val".). Such a misreading could result in a thousandfold overdose of a drug or medicine. However, mcg is also the symbol for the obsolete unit millicentigram, derived from the centimetre–gram–second system of units and equal to 10 μg.
Typography
Usually, a sequence of the Unicode code point Template:Unichar followed by the Latin letter Template:Unichar should be used. However, if μ is not available it may be represented with Template:Unichar or the legacy Unicode symbol Template:Unichar. In Chinese, Japanese and Korean writing a fullwidth version Template:Unichar should be used.[4]
See also
- List of SI prefixes
- Orders of magnitude (mass), listing a few items that have a mass of around 1 μg.
References
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- ↑ Script error: No such module "citation/CS1".
- ↑ NIST Handbook 133 - 2018, Appendix E. General Tables of Units of Measurement, page 159 (17)
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