Basic Evaluation of Chlamydia Antigen Detection by EIA Using a Dual Amplification Enhanced Immunoassay Method

Abstract

Chlamydia trachomatis is one of the important pathogens of STD in our country. Therefore, rapid accurate, reliable and convenient tests for its detection are required. So far, IDEIA^TM Chlamydia has been employed as a useful diagnostic kit. Now, IDEIA^TM PCE Chlamydia, applied as a dual amplification EIA method, has been developed. In our present studies, the sensitivity, reproducibility, cross reactivity, and reliability of IDEIATM PCE Chlamydia were investigated and compared with those of IDEIA^TM Chlamydia and LCR Chlamydia. The sensitivity of IDEIA^TM PCE Chlamydia showed 2.4×10² IFU/ml for C. trachomatis D, 1.2×10² IFU/ml for C. trachomatis E, 3.8×10 IFU/ml for C. trachomatis F, and 1.25×10² IFU/ml for C. trachomatisL2. With regard to reproducibility, more than 2.4×10² IFU/ml of all strains of C.trachomatisand negative samples gave highly reproducible values. Though no cross reactivity was recognized among three strains of Straphylococcus aureus with concentrations of more than 10⁹ IFU/ml, non-heated samples of over 10⁶ CFU/ml showed cross reactivity. In our observations, phosphate, Mg²⁺, Ca²⁺, and Fe³⁺ inhibited the efficacy of both IDEIA^TM and IDEIA^TM PCE Chlamydia. Ca²⁺Per se could be an inhibitor in the case of urine samples analyzed by IDEIA^TM and IDEIA^TM PCE Chlamydia. These results indicate that IDEIATM PCE Chlamydia kit for detection of C. trachomatis may be clinically useful because of its improved sensitivity over IDEIA^TM Chlamydia and its invariable specificity and reliability.