Pediatrics Immunization 0372cd74 Protective levels of Tetanus anti-toxin is: A >0.01 IU/mL B >0.5 IU/mL C >1.0 IU/mL D >5 IU/mL High-Yield Explanation a. >0.01IU/mL(Ref: Nelson's 20/e p 1381, Ghai 8/e p 193-194)Protective titer for diphtheria >0.1IU/mL and for tetanus >0.01IU/mL.