photo      This Legionella Urinary Antigen ELISA Test has been FDA cleared as an adjunct to culture for the presumptive diagnosis of past or current Legionnaires’ disease by qualitative detection of Legionella pneumophila serogroup 1 antigen in human urine.
     During a retrospective study on clinically well characterized urine specimens, 234 specimens were tested with both this LUA ELISA test and a commercial LUA ELISA. This trial consisted of urine specimens from 94 L. pneumophila serogroup 1 culture-positive individuals and 140 culture-negative individuals including non-Legionella pneumonia, bacteremia, miscellaneous pulmonary diseases and urinary tract infections.
      The performance of this ELISA and the commercial LUA ELISA were as follows: sensitivity 94.7 percent for this LUA ELISA, 87.2 percent for commercial ELISA; specificity was 89.3 percent for this ELISA, 83.6 percent for the commercial ELISA, and accuracy was 91.4 percent for this LUA ELISA and 85.0 percent for the commercial test.
     This LUA ELISA kit features rapid detection capabilities with a total incubation time of 90 minutes. It can be used by large and small testing facilities. The kit’s breakaway microwells can be washed by hand or with an automated plate washer.
     The test uses the antigen sandwich ELISA design for the detection of Legionella Urinary Antigen. The microelisa wells are pre-coated with purified rabbit antibodies. Undiluted urine specimens placed in the microelisa wells are followed by the immediate addition of conjugate. If LUA is present, an immune complex forms between the capture antibody, antigen and conjugate antibody, with all three elements bound to the ELISA plate well.
     Colorimetric substrate is then added and incubated, followed by the addition of stop solution. The stopped plate is then read visually or on a plate reader. The color intensity is directly proportional to the amount of antigen present.
     A positive result is assigned to any specimen whose optical density is greater than or equal to the Positive Cutoff.
Keyword: LUA ELISA