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The Lyra™ Adenovirus Assay is a real-time polymerase chain reaction (PCR) in vitro diagnostic test for the qualitative detection of human adenovirus (HAdV) viral DNA isolated from nasal and nasopharyngeal swab specimens obtained from individuals exhibiting signs and symptoms of acute respiratory infections. The intended use of this test is to aid in the diagnosis of HAdV in conjunction with other clinical and laboratory findings.

The test detects, but does not differentiate. HAdV species (A, B, C, D, E, and F) or serotypes (HAdV 1-52).

Negative results do not preclude HAdV infection and should not be used as the sole basis for diagnosis, treatment or other patient management decisions.

The Lyra™ Adenovirus Assay is a real-time polymerase chain reaction (PCR) in vitro diagnostic test for the qualitative detection of human adenovirus (HAdV) viral DNA isolated from nasal and nasopharyngeal swab specimens obtained from individuals exhibiting signs and symptoms of acute respiratory infections. The assay detects viral nucleic acids that have been extracted from a patient sample. A real-time PCR reaction is carried out using the ABI 7500 Fast Dx Real-Time PCR Instrument ("ABI Fast Dx Instrument") under optimized conditions in a single tube generating amplicons for adenovirus and the Process Control (PRC). Identification of human adenovirus (HAdV) and the PRC occurs by the use of target-specific primers and fluorescent-labeled probes that hybridize to conserved regions in the genomes of adenovirus and the PRC.

The Lyra™ Adenovirus Assay is a real-time Polymerase Chain Reaction (PCR) in vitro diagnostic test for the qualitative detection of human adenovirus (HAdV) viral DNA from nasal and nasopharyngeal swab specimens. Its intended use is to aid in the diagnosis of HAdV in individuals showing symptoms of acute respiratory infections. The device detects HAdV species (A, B, C, D, E, and F) or serotypes (HAdV 1-52) but does not differentiate them.

1. Table of Acceptance Criteria and Reported Device Performance:

The document does not explicitly state "acceptance criteria" with numerical thresholds. However, it presents performance data that would implicitly serve as the criteria for substantial equivalence. Based on the provided clinical study results, the implied acceptance criteria would likely be high sensitivity and specificity against the reference methods.

2. Sample size used for the test set and the data provenance:

Prospective Study (Test Set 1):

• Sample Size: 1241 fresh upper respiratory tract specimens initially, reduced to 1239 after excluding two invalid specimens.
• Data Provenance: Multi-center, prospective study. The document does not specify the exact countries of origin, but generally, FDA submissions imply US-based clinical studies unless otherwise stated. Specimens were collected and transported to labs daily and tested within 72 hours.

Retrospective Study (Test Set 2):

• Sample Size: 105 frozen upper respiratory tract specimens.
• Data Provenance: Retrospective study conducted at Site 1 (a pediatric hospital in the Southwest United States).

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

The document does not specify the number or qualifications of experts used to establish the ground truth for the clinical studies.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:

Prospective Study:

• The ground truth (reference method) for the prospective study was a "composite method of direct fluorescent antibody staining (CDFA) followed by direct fluorescent antibody staining of the specimen (SDFA)."
• A specimen was considered positive if either CDFA or SDFA was positive.
• A specimen was considered negative if both CDFA and SDFA were negative.
• This method effectively acts as an adjudication by combining two established diagnostic methods. There isn't a stated number of human readers for each method, but CDFA and SDFA are laboratory techniques with their own interpretation protocols, likely performed by trained laboratory personnel.

Retrospective Study:

• The reference method for the retrospective study was an "additional FDA-cleared molecular device" (a comparator PCR assay). There is no mention of adjudication for this comparative analysis.

5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

This device is an in vitro diagnostic (PCR-based assay) and not an AI-powered diagnostic tool for human readers. Therefore, an MRMC comparative effectiveness study involving human readers with/without AI assistance was not performed and is not relevant to this submission.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

The performance reported for the Lyra™ Adenovirus Assay (sensitivity, specificity, positive percent agreement, negative percent agreement) in both the prospective and retrospective studies represents the standalone performance of the device (algorithm/assay only) compared to the respective reference methods. This indicates the device's ability to detect HAdV without human interpretation affecting the outcome of the assay itself, although humans are involved in performing the test and interpreting the final qualitative result generated by the instrument.

7. The type of ground truth used:

• Prospective Study: A "composite method" of direct fluorescent antibody staining (CDFA) of viral culture and direct fluorescent antibody staining of the specimen (SDFA). This is a laboratory-based reference method, essentially a combination of viral culture and expert interpretation of fluorescent antibody staining.
• Retrospective Study: An "additional FDA-cleared molecular device" (a comparator FDA-cleared PCR assay).

8. The sample size for the training set:

The document does not explicitly describe a separate "training set" in the context of machine learning. For in vitro diagnostic assays like this, method development and optimization phases typically involve extensive internal testing and reagent optimization, which would be analogous to "training" certain parameters. However, the document provided focuses on the analytical and clinical validation studies.

9. How the ground truth for the training set was established:

As noted in point 8, a distinct "training set" with ground truth in the machine learning sense is not detailed. The development process of the Lyra™ Adenovirus Assay would have involved establishing its limits of detection (LoD) using quantified viral stocks (e.g., TCID50/mL), assessing inclusivity against known serotypes, and testing for cross-reactivity and interference against quantified organisms. These are established through recognized laboratory standards and methodologies rather than "ground truth" derived from expert consensus on patient cases in a training set.

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