Rules for use of SI-prefixes in laboratory medicine
- SI prefix table (modified)
- Various expressions of SI units
- Unit one or SI factor as measurement units
|SI prefixes are a set of multiples and submulitples within the SI system
|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
|Factor (SI factor)
|Term (SI prefix name)
|Symbol (SI prefix)
Note: SI prefixes (deci (d), centi (c), deca (Da), and hecto (H) are not allowed or displayed due to a less distance than 1000 between the next SI prefixes.
A measurement unit can be expressed with several combinations of SI prefix and SI factors that may placed in the denominator and numerator.
To avoid confusion and misunderstanding with various different expressions of the same unit, a preferred unit symbol should be used.
Examples of various unit symbols for the same measurement unit
Note: The last unit symbol, gram per decilitre, is not recommended to use because the distance between g/dL and g/L is only a factor 10.
|Kinds-of-quantity of dimension one (e.g. mass fraction, substance ratio, number concentration) may have “one” or SI factors as corresponding measurement units.
There are several combinations of unit symbols for SI factors.
To avoid confusion and misunderstanding with several unit symbols for the same measurement unit, the measurement unit equation undergoes a linear algebraic reduction.
The linear algebraic reduction will change the unit equation into a simpler form.
Note 1: When SI factors are used as measurement units, it is in particular important to display the kind-of-quantity along the measurement unit, to understand the measurement unit
Note 2: The same SI factor may be used as measurement unit for different kinds-of-quantity
Linear algebraic reduction of a measurement unit equation into a SI factor that is the preferred unit symbol.
The same SI factor can be used as corresponding measurement unit for other kinds-of-quantity.