Abstract
An immunochromatographic assay kit is frequently used in the diagnosis of legionellosis. We evaluated the usefulness of Immunocatch®-Legionella, a newly developed immunochromatographic assay kit for the detection of the Legionella antigen. The kit showed a higher detection sensitivity than BinaxNOW® Legionella and Check-Legionella, and showed an equivalent detection sensitivity to Q-line Kyokuto Legionella. In addition, Immunocatch®-Legionella as well as Q-line Kyokuto Legionella showed the most rapid determination. A total of 100 specimens from patients with pneumonia symptoms were tested using these immunochromatographic assay kits. The positive agreement, negative agreement, and overall agreement rates of Immunocatch®-Legionella and BinaxNOW® Legionella were 100% (1/1), 99.0% (98/99), and 99.0% (99/100), respectively. One case was negative as determined using BinaxNOW® Legionella, but was positive as determined using Immunocatch®-Legionella. The use of a concentrated specimen of this case resulted in a positive result using BinaxNOW® Legionella. These results suggest that BinaxNOW® Legionella has an insufficient sensitivity, and the determination using it may lead to a false-negative result. Immunocatch®-Legionella has a simpler procedure and higher sensitivity than the other kits. It also showed good performance with clinical specimens. In conclusion, Immunocatch®-Legionella is a clinically useful rapid diagnostic kit for the detection of Legionella antigen.
