Titer

Titer (American English) or titre (British English) is a way of expressing concentration.[1] Titer testing employs serial dilution to obtain approximate quantitative information from an analytical procedure that inherently only evaluates as positive or negative. The titer corresponds to the highest dilution factor that still yields a positive reading.[2] For example, positive readings in the first 8 serial, twofold dilutions translate into a titer of 1:256 (i.e., 2−8). Titres are sometimes expressed by the denominator only, for example 1:256 is written 256.[3]

The term also has two other, conflicting meanings. In titration, the titer is the ratio of actual to nominal concentration of a titrant, e.g. a titer of 0.5 would require 1/0.5 = 2 times more titrant than nominal. This is to compensate for possible degradation of the titrant solution. Second, in textile engineering, titre is also a synonym for linear density.

  1. ^ Michael G. Kaplitt; Arthur D. Loewy (August 1, 1995). Viral vectors: gene therapy and neuroscience applications. Academic Press. p. 304. ISBN 978-0-12-397570-6. Retrieved March 18, 2012.
  2. ^ Morag Crichton Timbury (1994). Notes on medical virology. Churchill Livingstone. p. 27. ISBN 978-0-443-04872-2. Retrieved March 18, 2012.
  3. ^ Harold E. Fox; Jessica Bienstock (December 21, 2010). The Johns Hopkins Manual of Gynecology and Obstetrics. Lippincott Williams & Wilkins. p. 226. ISBN 978-1-60547-433-5. Retrieved March 18, 2012.