Abstract: | The possibility of using, on principle, the enzyme immunoassay (EIA) in different modifications for the detection of S. typhi L-forms in biological fluids (blood, urine) was established. The inhibiting variant of EIA showed the highest sensitivity: 1 ng/ml. The direct sandwich variant permitted the quantitative determination of the antigen of S. typhi L-form in the widest range of 20-500 ng/ml. The indirect enzyme immunometric variant permitted the detection of S. typhi L-forms with a sensitivity of 10(5) colony-forming units per ml only in urine. |