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OD Unit

  1. Paul H Dear

Published Online: 23 SEP 2005

DOI: 10.1038/npg.els.0005331



How to Cite

Dear, P. H. 2005. OD Unit. eLS. .

Author Information

  1. Medical Research Council Laboratory of Molecular Biology, London, UK

Publication History

  1. Published Online: 23 SEP 2005


An OD unit is a unit of concentration or (loosely) mass, particularly of solutions of nucleic acids or suspensions of bacterial or yeast cells. It is derived from the degree of absorption of light at a specified wavelength by the solution or suspension.


  • optical density;
  • deoxyribonucleic acid;
  • ribonucleic acid