Rapid detection of enteric fever by coagglutination and countercurrent immunoelectrophoresis.

A total of 463 patients clinically suspected of enteric fever and 100 healthy individuals were investigated by coagglutination (COAG) and countercurrent immunoelectrophoresis (CIEP) for rapid diagnosis of enteric fever. The S. typhi was grown in blood culture in 32 (6.91%) and Widal test was positive in 126 (27.21%) cases. The serum COAG with local antiserum was positive in 165 (35.64%), serum COAG with standard antiserum in 163 (35.21%), Blood culture supernatant (BCS) COAG in 153 (33.05%), serum CIEP for antigen (Ag) in 118 (25.09%), BCS CIEP in 99 (21.39%) while serum CIEP for antibody (Ab) was positive in 34 (7.34%) cases. Only two healthy controls revealed positive COAG result with local antiserum. The sensitivity of all antigen detection tests was 100% except BCS CIEP (98.25%) in the first week of fever and declined rapidly to 75.79% for serum COAG tests, 69.47% for BCS COAG and dramatically to 37.89% for serum CIEP for Ag and 22.11% for BCS CIEP tests during the second week whereas the sensitivity of serum CIEP for Ab detection rose from 17.54% to 23.16% from first to second week of illness. In view of the resulting data, it is suggested that both COAG and CIEP may be employed for the rapid diagnosis of enteric fever in the routine clinical setup.