Rules for use of SI-prefixes in laboratory medicine
- Overview
- SI prefix table (modified)
- Various expressions of SI units
- Various expressions of SI factors units
Definition | SI prefixes are a set of multiples and submulitples within the SI system |
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Purpose of the use of SI-prefixes |
To prevent communication errors due to several expressions of the same unit To ensure that the numerical values in laboratory results are human readable and understandable |
Principles |
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Rules |
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Reference |
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Factor | Term | Symbol |
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10–24 | yocto | y |
10–21 | zepto | z |
10–18 | atto | a |
10–15 | femto | f |
10–12 | pico | p |
10–9 | nano | n |
10–6 | micro | µ |
10–3 | milli | m |
103 | kilo | K |
106 | mega | M |
109 | giga | G |
1012 | tera | T |
1015 | peta | P |
1018 | exa | E |
1021 | zetta | Z |
1024 | yotta | Y |
Note: SI prefixes (deci (d), centi (c), deca (Da), and hecto (H) are not allowed or displayed
Principle |
One expression per unit |
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Background | A unit can be expressed in several combinations. It is to avoid confusion about different expressions of the same unit. |
Examples |
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Rules |
One SI prefix per unit
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Reference |
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Preferred unit term | Examples of non-recommended unit terms | |||||||||||
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SI factor | Gram | Litre | Mol | Factors (number) | ||||||||
10–12 | ||||||||||||
10–9 | ||||||||||||
10–6 | ||||||||||||
10–3 | ||||||||||||
1 | ||||||||||||
103 | ||||||||||||
106 | ||||||||||||
109 | ||||||||||||
1012 |