A Sharon Miller, a member of the MLO editorial advisory board, assisted me in answering this question. Clinical laboratory sciences students at Northern Illinois University receive the following information as part of their initial lab guidelines:
Terminology of dilutions is very important. Unfortunately, there is inconsistency in how dilutions are described. When water is added to relatively concentrated solutions or mixtures, they are being diluted. We say, for example, that we make a "1 in 10" dilution. This means that one volume of concentrate is mixed with nine volumes of water. A "1 in 100" dilution is one volume of concentrate in 99 volumes of water.
Avoid the expression "one-to-one dilution" or "one-to-two dilution." Those expressions are actually proportions, not dilutions. We can express dilutions as follows: a "1 in 10" dilution = 1:10; and "1 in 100" dilution = 1:100. A 1:2 or "1 in 2" dilution is prepared by taking 200 mL of concentrate and adding 200 mL of water to create 40 mL of solution.
--Daniel M. Baer, MD
Department of Pathology
Oregon Health and Science University
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|Title Annotation:||Answering your questions|
|Author:||Baer, Daniel M.|
|Publication:||Medical Laboratory Observer|
|Article Type:||Brief article|
|Date:||Nov 1, 2007|
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