Lambda (unit)

Lambda (written λ, in lowercase) is a nonstandard metric unit of volume equal to 10⁻⁹ m³, 1 cubic millimeter (mm³) or 1 microlitre (µL). Introduced by the BIPM in 1880,^[1] the lambda has been used in chemistry^[2] and in medicine for measuring small volumes, but its use is no longer recommended.^[3]

This use of λ parallels the pre-SI use of µ on its own for a micrometre and γ for a microgram.^[4][5] Although the use of λ is deprecated, some clinical laboratories continue to use it.^[6] The standard abbreviation µL for a microlitre has the disadvantage that it can be misread as mL (a unit 1000 times larger), and in pharmaceutical use no abbreviation for a microlitre is considered safe; recommended practice is to write "microlitre" in full.^[7]

References

1. Donald Fenna (2002), A Dictionary of Weights, Measures, and Units, Oxford University Press, ISBN 0198605226, p. 153.
2. "Units: L". University of North Carolina. Retrieved 2015-03-28.
3. Carl A. Burtis and David E. BrunsTietz (2014), Fundamentals of Clinical Chemistry and Molecular Diagnostics, 7th ed., Elsevier Health Sciences, ISBN 0323292062, p. 114.
4. Lela Buckingham (2014), Fundamental Laboratory Mathematics: Required Calculations for the Medical Laboratory Professional, F. A. Davis, ISBN 0803641028, p. 48.
5. I. P. Alimarin and M. N. Petrikova (2013), Inorganic Ultramicroanalysis, Elsevier, ISBN 1483150488, p. xiv.
6. Barbara H. Estridge, Anna P. Reynolds, and Norma J. Walters (2000), Basic Medical Laboratory Techniques, 4th ed., Cengage Learning, ISBN 0766812065, p. 32.
7. Chris Langley and Yvonne Perrie (2014), Maths Skills for Pharmacy: Unlocking Pharmaceutical Calculations, Oxford University Press, ISBN 019968071X, p. 55.