Rapid indirect haemagglutination (rapid-IHA) using sensitized chick cells for serodiagnosis of amoebiasis at primary health centre level.

A successful modification of the indirect haemagglutination (IHA) test as a simple and rapid diagnostic procedure for serodiagnosis of amoebiasis at a primary health centre (PHC) level laboratory has been described in the present study. In this modified IHA test, the chick red blood cells (RBC), stabilized by the double aldehyde method, could be sensitized with amoebic antigen and then stored at 4 degrees C for up to 45 days for their subsequent use, as ready-made reagent directly in the IHA, without loss of sensitivity. The chick red cells settled quickly and their haemagglutination pattern could be determined within 30 to 45 min of incubation at room temperature with test sera. The IHA using double-aldehyde stabilized (DAS) chick cells, showed equal sensitivity and specificity with that of IHA using human O cells in diagnosing cases with different manifestations of amoebiasis. With the use of stored sensitized DAS chick cells directly in the IHA, the test could be performed and results obtained within 60 to 90 min of receipt of the sera to be tested. This makes IHA a simple and rapid procedure for its adaptation at a PHC level laboratory for the serodiagnosis of amoebiasis.