Todd unit

Todd u·nit

the unit in which the results of testing for antistreptolysin O (ASO) are expressed. It denotes the reciprocal of the highest dilution of test serum at which there continues to be neutralization of a standard preparation of the streptococcal enzyme streptolysin O.

Todd unit

(tŏd)
In a test of inhibition hemolysis by enzymes such as antistreptolysin O, the reciprocal of the highest dilution that inhibits hemolysis.
References in periodicals archive ?
Physical examinations and investigations (including complete blood count (CBC), biochemical analyses, cardiological evaluation, hs-CRP (high-sensitivity C-reactive protein) were normal, but serum Antistreptolysin O (ASO) titer was 1333 Todd units (Normal value: 170-330 Todd units) and Erythrocyte Sedimentation Rate (ESR) value was 32/first hour (Normal 0-10).
He did not report any compulsion six weeks later and ESR and ASO value reduced to 22/first hour and 1248 Todd units, respectively.
Initial laboratory examination revealed a white blood cell count of 13,000/ml, sedimentation rate of 85 mm/h, C-reactive protein: 132 mg/dl, Antistreptolisin O (ASO): 870 Todd units (normal<200).