The use of DIGFA for the detection of circulating antigens in sera of patients with cysticercosis

Aim To set up a method that can diagnose cysticercosis rapidly and sensitively.Methods Two McAbs against cyst fluid antigen of cysticercus cellulosae,one absorbed on nitrocellulose membrane,another conjugated to colloidalgold,were used to develop a dot immunogold filtration assay(DIGFA)for the detection of circulating antigens(CA) in sera of patients with cysticercosis.Antigen-antibody reaction was completed on the membrane during the filtration process.The result could be read with the naked eye within ten minutes.DIGFA and ELISA were compared. Results 68 of 78 sera from cysticercosis were positive.The positive rat was 87.18%.Of the 78 sera from cysticercosis,51 of 52(98.08%)sera from active neurocysticercosis,13 of 20(65.00%)sera from inactive neurocysticercosis and 4 of 6( 66.67%)sera from cysticercosis of simple subcutaneous nodules type were positive.Only one out of 40 sera from normal population showed positive.None of 10 sera from patients with clonorchiasis,15 sera from patients with schistosomiasis and 23 sera from patients with other diseases of the central nervous system was positive.The minimal detectable level of DIGFA was 0.45ng/ml.DIGFA and ELISA had a similar sensitivity and specificity.The coincidence rat was 98.19%.However,DIGFA was simpler and easier to conduct and required no instrument.Conclusion DIGFA is suitable for diagnosis of cysticercosis,especially for active neurocysticercosis.