Evaluation of Indirect Fluorescent Antibody Technique for Detection of Rabies Antibody in Human Sera Free

Five hundred and eighty-eight sera were tested by the serum neutralization (SN) and indirect fluorescent rabies antibody (IFRA) procedures. Of 285 positive sera by the SN test, 280 (98.3%) were also positive by the IFRA method, indicating acceptability of the IFRA test as a screening procedure for the detection of rabies antibody. Seventy-eight sera from rabies-immunized people were positive by the IFRA method and negative by the SN method, indicating a greater sensitivity of the IFRA test. Further investigations are needed to define the relationship of demonstrable rabies antibody to protection against rabies virus challenge.