Definition of titer in English:



(British titre)
  • 1Chemistry
    The concentration of a solution as determined by titration.

    ‘Dialysis of the DNA resulted in acceptable titres.’
    • ‘The plate is incubated at 37° for 16-36 hr, and the titer of the colony-forming units is divided by the titer of the microscopic count to determine the viability.’
    • ‘Aliquots were withdrawn at the indicated times, the viable titer was determined, and the percentage of survivors was calculated.’
    • ‘Samples of the co-cultures were examined on different indicator plates to allow the determination of the titer of each strain and of the wild type, taking advantage of markers that were present in each lineage.’
    • ‘Hormone titers and titer regulators have only been measured in two cricket species, and even these basic pieces of endocrine information are lacking in aphids and planthoppers, despite decades of study.’
    1. 1.1The minimum volume of a solution needed to reach the endpoint in a titration.
    2. 1.2Medicine The concentration of an antibody, as determined by finding the highest dilution at which it is still able to cause agglutination of the antigen.
      ‘The antibody response was termed as group specific, species specific or cross reactive depending on the comparative antibody titres obtained against different antigen pools.’
      • ‘Patients in Stages III and IV showed a decline in the antiGDlb antibody titers in relation to neurological recovery following PE.’
      • ‘Influenza vaccination has produced substantial antibody titers against influenza in vaccinated HIV-infected persons who have minimal symptoms related to acquired immunodeficiency syndrome and high CD4 cell counts.’
      • ‘Though significantly high titres indicate an acute infection, rise in titres of antibodies in serum samples collected one week apart is diagnostic.’
      • ‘Patients with lower antibody titers to varicella after vaccination also had an increased rate of breakthrough infection.’



/ˈtīdər/ /ˈtaɪdər/


Mid 19th century from French, from titrer (see titrate).