Serological evaluation of thin-layer immunoassay-enzyme-linked immunosorbent assay for antibody detection in human trichinellosis

A new immunoenzymatic test, named the thin-layer immunoassay-enzyme-linked immunosorbent assay (TIA-ELISA), was evaluated for antibody detection in hu man trichinellosis using excretion and secretion products prepared from Tri chinella spiralis muscle larvae. Serum samples from people with positive mu scle biopsies or symptoms compatible with the disease (rt = 8 or 26, respec tively), all reactive in enzyme-linked immunoelectrotransfer blot assay (EI TB), as well as 67 serum samples from healthy, EITB-negative people, were t ested in an ELISA and TIA-ELISA. TIA-ELISA was performed in polystyrene pla stic petri dishes by adding dots of 10 mu l each of antigen (7 mu g/ml) fol lowed by adding diluted serum and the conjugate. Finally, the substrate mix ed with agar was added to develop the reaction. Enzymatic by-products were easily detected by the naked eye as defined dots. Sensitivity and specifici ty were 76 and 94% for ELISA, and both parameters were 91% for TIA-ELISA. T he kappa correlation indices for both tests in relation to EITB were 0.73 a nd 0.80, respectively. The TIA-ELISA can be carried out with common laborat ory equipment in 3 h and uses lower quantities of antigen than EITB and ELI SA, Since TIA-ELISA is easy to perform, cheap, sensitive, and specific, the test could be an acceptable alternative to use in clinical laboratories la cking specialized equipment needed for ELISA and EITB and in field studies for antibody detection in human trichinellosis.