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The SAS™ Legionella Test is a visually read, in vitro immunochromatographic rapid assay for the presumptive qualitative detection of Legionella pneumophila serogroup 1 antigens in human urine. This test is intended to aid in the presumptive diagnosis of Legionnaires' disease in conjunction with culture and other methods for patients with signs and symptoms of pneumonia. This test is for prescription use only.

The SAS™ Legionella test utilizes a combination of polyclonal antibodies against the antigens of Legionella pneumophila. The SAS™ Legionella test begins with the addition of urine to the test device. The specimen is absorbed by the sample pad and then moves through the conjugate pad which contains dried gold conjugated antibodies which are specific for Legionella pneumophila antigens; if the Legionella antigens are present in the urine sample, a "half-sandwich" immunocomplex is formed. This immuno-complex then migrates via capillary action along a nitrocellulose membrane containing immobilized antibodies to Legionella pneumophila antigens. The immobilized antibodies bind the "half-sandwich" immuno-complex to form a "whole sandwich" immuno-complex. Thus, when the "whole sandwich" is formed, a visible, pink colored line develops in the specimen zone on the test device. In the absence of a Legionella antigen, a "sandwich" immuno-complex is not formed and a negative result is indicated. To serve as a procedural control, a pink colored control line will always appear in the control zone regardless of the presence or absence of Legionella antigen. The test is available in cassette format.

{
  "1_table_of_acceptance_criteria_and_reported_device_performance": {
    "Acceptance Criteria (Implicit)": "To demonstrate substantial equivalence to the predicate device (Binax™ Now® Legionella Urinary Antigen Test) and to culture methods for the detection of Legionella pneumophila serogroup 1 antigens in human urine.",
    "Reported Device Performance": "The SAS™ Legionella Test performed substantially equivalent to the predicate device, Binax™ Now® Legionella Urinary Antigen Test and to culture. Cross reactivity and interference studies showed no interference or cross-reaction with common viral and bacterial strains found in human urine."
  },
  "2_sample_size_used_for_the_test_set_and_data_provenance": {
    "Sample Size (Test Set)": "Not explicitly stated. The document mentions \"frozen and fresh urine specimens\" were used for comparison but does not provide a specific number.",
    "Data Provenance": "Not explicitly stated (e.g., country of origin). The data is retrospective based on the use of \"frozen and fresh urine specimens\" for comparison."
  },
  "3_number_of_experts_used_to_establish_the_ground_truth_for_the_test_set_and_qualifications": "Not applicable. The ground truth was established by comparison to a predicate device (Binax™ Now® Legionella Urinary Antigen Test) and culture methods, not by expert interpretation of the device results.",
  "4_adjudication_method_for_the_test_set": "Not applicable. Adjudication methods like 2+1 or 3+1 are typically used for expert consensus on image interpretation, which is not relevant for this immunochromatographic rapid assay.",
  "5_if_a_multi_reader_multi_case_mrmc_comparative_effectiveness_study_was_done": "No. This is an immunochromatographic rapid assay, not an imaging device requiring human reader interpretation in a MRMC study.",
  "6_if_a_standalone_performance_study_was_done": "Yes. The performance of the SAS™ Legionella Test (algorithm only, as it's a diagnostic kit) was directly compared against established methods (predicate device and culture) for diagnostic accuracy.",
  "7_the_type_of_ground_truth_used": "Comparison to a legally marketed predicate device (Binax™ Now® Legionella Urinary Antigen Test) and culture methods. Culture is generally considered a gold standard for bacterial identification.",
  "8_the_sample_size_for_the_training_set": "Not applicable. As a diagnostic test kit, there isn't a 'training set' in the machine learning sense. The device is developed through biochemical assays and optimizations, not by training an algorithm on a 'training set' of data.",
  "9_how_the_ground_truth_for_the_training_set_was_established": "Not applicable. See #8. The development of such a test relies on established scientific principles of immunology and antigen-antibody reactions, and validation against known Legionella-positive and -negative samples, rather than a 'ground truth' established for a training set in machine learning."
}

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