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.
Etymology
Titer has the same origin as the word "title", from the French word titre, meaning "title" but referring to the documented purity of a substance, often gold or silver. This comes from the Latin word titulus, also meaning "title".
Examples
Antibody titer
An antibody titer is a measurement of how much
Many traditional serological tests such as
Other examples
A viral titer is the lowest concentration of a virus that still infects cells. To determine the titer, several dilutions are prepared, such as 10−1, 10−2, 10−3, ... 10−8.[1]
The titer of a fat is the temperature, in degrees Celsius, at which it solidifies.[4] The higher the titer, the harder the fat. This titer is used in determining whether an animal fat is considered tallow (titer higher than 40 °C) or a grease (titer below 40 °C).[5]
See also
- Serology
- Titration
- W/v
- Mg%
- Virus quantification
- Viral titer
References
- ^ ISBN 978-0-12-397570-6. Retrieved March 18, 2012.
- ISBN 978-0-443-04872-2. Retrieved March 18, 2012.
- ISBN 978-1-60547-433-5. Retrieved March 18, 2012.
- ISBN 978-1-4200-6166-6. Retrieved March 18, 2012.
- ISBN 0-9786349-0-X. Retrieved July 11, 2009.