Method Description

The BINAXNOW Legionella Urinary Antigen Test is an immunochromatographic membrane assay to detect Legionella pneumophila serogroup 1 soluble antigen in human urine. Rabbit anti-L pneumophila serogroup 1 antibody (the patient line) is adsorbed onto nitrocellulose membrane. Goat-anti-rabbit IgG (the control line) is adsorbed onto the same membrane as a second stripe. Rabbit anti-L pneumophila serogroup 1 antibodies are conjugated to visualizing particles that are dried onto an inert fibrous support. The resulting conjugate pad and the striped membrane are combined to construct the test strip. This test strip and a well to hold the swab specimen are mounted on opposite sides of a hinged, book-shaped test device.

To perform the test, a swab is dipped into the urine specimen, removed, and then inserted into the test device. Reagent A is added from a dropper bottle. The device is then closed, bringing the specimen into contact with the test strip. L pneumophila serogroup 1 urinary antigen captured by immobilized anti-L pneumophila serogroup 1 antibody reacts to bind conjugated antibody. Immobilized goat-anti-rabbit IgG also captures visualizing conjugate, forming the control line. A positive test result is visually read in 15 minutes or less depending on the concentration of antigen present in the urine specimen. A negative result, read in 15 minutes, indicates that L pneumophila serogroup 1 antigen was not detected in the urine specimen.

The test is interpreted by the presence or absence of visually detectable pink-to-purple colored lines. A positive result will include the detection of both a patient and a control line, while a negative assay will produce only the control line. Failure of the control line to appear, whether the patient line is present or not, indicates an invalid assay.(Package insert: BinaxNow Legionella Urinary Antigen Card. Abbott Diagnostics; IN852050 Rev.12, 01/2021)