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The PANBIO West Nile Virus IgG Indirect ELISA is for the qualitative presumptive detection of IgG antibodies to West Nile virus in serum. In conjunction with the PANBIO West Nile Virus IgM Capture ELISA, this test is intended as an aid in the clinical laboratory diagnosis of West Nile virus infection in patients with clinical symptoms consistent with encephalitis / meningitis. Positive results must be confirmed by plaque reduction neutralization test (PRNT), or by using the current Centers for Disease Control and Prevention (CDC) guidelines for diagnosis of this disease.

The PANBIO West Nile Virus IgG Indirect ELISA is for the qualitative detection of IgG antibodies to West Nile virus in serum. In conjunction with the PANBIO West Nile Virus IgM Capture ELISA, this test is intended as an aid in the presumptive laboratory diagnosis of West Nile virus infection in patients with clinical symptoms consistent with encephalitis / meningitis.

Acceptance Criteria and Device Performance for PANBIO West Nile Virus IgG Indirect ELISA

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for this device are not explicitly stated as numerical targets in the provided text (e.g., "sensitivity must be > X%"). Rather, the studies aim to demonstrate adequate performance through descriptive statistical measures (sensitivity, specificity, positive and negative presumptive agreement) and reproducibility. The performance is reported with 95% Confidence Intervals. The cross-reactivity study aims to show the device's analytical specificity.

2. Sample Sizes and Data Provenance for Test Sets

• Study Site 1 (Louisiana, USA):

  • Sample Size: 300 retrospective sera.
  • Data Provenance: Louisiana, USA. Retrospective samples collected in 2002-2003.

• Study Site 2 (Utah, USA):

  • Sample Size: 325 retrospective sera.
  • Data Provenance: Utah, USA. Retrospective samples.

• Study Site 3 (Ohio, USA):

  • Sample Size: 284 retrospective sera.
  • Data Provenance: Ohio, USA. Retrospective samples collected in 2002.

• Reproducibility Study:

  • Sample Size: 8 sera, tested 3 times each on 3 different assays (total 72 tests per parameter).
  • Data Provenance: One Australian study site and two study sites in the USA.

• Cross-Reactivity Study:

  • Sample Size: 314 specimens in total, with varying numbers per disease state.
  • Data Provenance: Multiple sites including PANBIO (Site 5), a state health laboratory in Louisiana (Site 1), a private reference laboratory in Utah (Site 2), a hospital laboratory in Ohio (Site 3), and a private research laboratory in Maryland (Site 6). The exact timing of collection for these cross-reactive samples is not specified beyond being "from patients with confirmed diseases other than WNV."

3. Number of Experts and Qualifications for Ground Truth

The document does not explicitly state the "number of experts" or their specific "qualifications" (e.g., "radiologist with 10 years of experience") for establishing the ground truth. However, the ground truth was established by:

• Plaque Reduction Neutralization Test (PRNT): This is a gold standard serological test, implying expert virological laboratory practices and interpretation.
• West Nile Virus IgG IFA (Immunofluorescence Assay): This is another standard serological method, likely performed and interpreted by trained laboratory personnel or experts.
• Clinical and serological characterization: This suggests a combination of clinical diagnosis and laboratory test results, presumably by medical professionals and laboratory specialists.
• Western blot analysis: Used for confirmation of flavivirus positivity in cross-reactivity samples, indicating expert serological techniques.

4. Adjudication Method for the Test Set

The document does not describe a formal "adjudication method" involving multiple human readers or a consensus process for discrepant results in the context of device performance evaluation (e.g., 2+1, 3+1 for image interpretation). Instead, the comparison is directly between the PANBIO ELISA results and the established "gold standard" or "characterization" of the specimens (PRNT, IgG IFA, or clinical characterization).

Equivocal results from the PANBIO ELISA were generally "not retested" due to sample unavailability or because the cut-off was modified post-clinical trials, indicating that a formal re-adjudication process for equivocal outcomes was not systematically applied within these studies.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No Multi-Reader Multi-Case (MRMC) comparative effectiveness study was done. The device is an in-vitro diagnostic (IVD) assay designed for laboratory testing, not an imaging device requiring human-in-the-loop interpretation. Therefore, the concept of human readers improving with or without AI assistance is not applicable to this device.

6. Standalone Performance

Yes, a standalone performance study was done. The entire evaluation presented (sensitivity, specificity, presumptive agreements, reproducibility, and cross-reactivity) describes the performance of the PANBIO West Nile Virus IgG Indirect ELISA algorithm/assay itself, without human-in-the-loop assistance in its operation or primary interpretation. The results are based on how the assay performs when processing samples and generating qualitative results (Positive, Equivocal, Negative).

7. Type of Ground Truth Used

The ground truth used for the test sets included:

• Expert Consensus/Reference Methods: Primarily, Plaque Reduction Neutralization Test (PRNT) and West Nile Virus IgG Immunofluorescence Assay (IFA) were used as reference methods to characterize samples as positive or negative for West Nile Virus IgG. These are established laboratory methods considered reliable.
• Clinical Characterization: Samples from patients with "clinical symptoms consistent with encephalitis/meningitis" were also used, implying correlation with patient presentation alongside serological markers.
• Disease State Confirmation: For the cross-reactivity study, samples were characterized by their "disease state" (e.g., Dengue virus, St. Louis encephalitis, Cytomegalovirus) and for some flaviviruses, confirmed by Western blot analysis.

8. Sample Size for the Training Set

The document does not explicitly mention a "training set" or "validation set" in the context of machine learning. This is an IVD assay, and the "training" of the assay's cut-off or parameters would typically involve internal development studies and optimization rather than a distinct "training set" like in AI/ML contexts. The performance characteristics described are based on testing against retrospectively collected "test sets" or panels of samples.

9. How the Ground Truth for the Training Set was Established

Since a distinct "training set" for an AI/ML algorithm is not described, the method for establishing its ground truth is not applicable in this context. The assay's performance evaluation relies on comparing its output to established reference methods (PRNT, IFA, Western blot) and clinical characterization using the "test sets" described above. The statement that "cut-off was modified following clinical trials" in Study Site 2 hints at an iterative process of optimizing the assay's interpretive criteria based on initial performance data.

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The PANBIO West Nile Virus IgM Capture ELISA is for the qualitative presumptive detection of IoM antibodies to West Nile virus in serum as an aid in the clinical laboratory diagnosis of West Nile virus infection in patients with clinical symptoms consistent with encephalitis / meningitis. Positive results must be confirmed by plaque reduction neutralization test (PRNT), or by using the current Centers for Disease Control and Prevention (CDC) guidelines for diagnosis of this disease.

Assay performance characteristics have not been established for testing cord blood, neonate, prenatal screening, general population screening without symptoms of meningioencephalitis or automated instruments. The user is responsible for establishing these assay performance characteristics.

Caution: Cross-reactivity has been noted with the PANBIO West Nile IgM assay in specimens containing rheumatoid factor (RF). Reactive results must be reported with a caution statement regarding possible cross-reactivity with RF.

The West Nile Virus IgM Capture ELISA is an Enzyme Linked Immunosorbent Assay (ELISA) for the qualitative detection of IgM antibodies to West Nile virus in serum as an aid in the clinical laboratory diagnosis of West Nile virus in patients with clinical symptoms consistent with encephalitis / meningitis.

Acceptance Criteria and Device Performance Study for PANBIO West Nile Virus IgM Capture ELISA

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria (e.g., "The device must achieve at least X% sensitivity and Y% specificity"). However, the performance characteristics obtained serve as the benchmark for clearance. Given the context of a 510(k) summary, the "reported device performance" essentially functions as the de facto acceptance criteria, demonstrating substantial equivalence to the predicate device.

*CI = Exact confidence interval
¹ Sixteen samples testing indeterminate by IFA and negative by PANBIO were assigned to "IgM positive" for worst-case.
² Seven samples testing indeterminate by IFA and positive by PANBIO were assigned to "IgM negative" for worst-case.

2. Sample Sizes Used for the Test Set and Data Provenance

• Study Site 1:
  • Total Samples: 420 retrospective sera
  • PRNT-confirmed subset: 130 samples (61 WNV positive, 69 WNV negative)
  • CDC MAC EIA presumptively characterized subset: 73 samples (11 WNV positive, 62 WNV negative)
  • IgM IFA presumptively characterized subset: 419 samples (96 IgM positive, 23 indeterminate, 300 negative) (Note: The sum is 419, not 420. One sample might have been excluded or lost from the initial 420).
  • Data Provenance (Country of Origin and Retrospective/Prospective): Retrospective sera from individuals in various locations:
    • California, USA (blood donation center)
    • Maryland, USA (private reference laboratory)
    • Utah, USA (private reference laboratory)
    • Texas, USA (university medical branch)
    • Minnesota, USA (private laboratory)
    • Canada (government medical laboratory)
• Study Site 2:
  • Total Samples: 51 retrospective sera confirmed by PRNT. These were encephalitis/meningitis patients.
  • Data Provenance (Country of Origin and Retrospective/Prospective): Retrospective sera from patients collected in 2002 at a hospital laboratory in Ohio, USA.
• Specificity of IgM Detection: 10 serum samples for DTT treatment, 8 serum samples for IgG interference. Provenance not specified but likely conducted in-house.
• Reproducibility: Not directly a test set for clinical performance; 27 observations for each of 9 samples.
• Cross-Reactivity: 160 specimens from patients with confirmed diseases other than WNV. Provenance not explicitly stated for individual samples, but the study was conducted at "Study Site 1" and "Study Site 2" (Ohio) and in-house at PANBIO.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The document does not explicitly state the number of experts or their specific qualifications (e.g., radiologist with X years of experience) who established the ground truth for the test sets. Instead, the ground truth was established by:

• Plaque Reduction Neutralization Test (PRNT): A laboratory method considered the gold standard for WNV confirmation. This is a laboratory assay, not an expert panel judgment in the traditional sense.
• CDC MAC EIA: Presumptive characterization based on another laboratory assay.
• WNV IgM IFA: Presumptive characterization based on another laboratory assay.

The characterization of specimens was performed by recognized laboratory methods, not by human expert adjudication of individual cases.

4. Adjudication Method for the Test Set

The ground truth for the clinical performance studies was established using laboratory reference assays:

• Plaque Reduction Neutralization Test (PRNT): Used to "confirm" WNV positive/negative status for the primary sensitivity/specificity calculations. This acts as the independent "adjudicator."
• CDC MAC EIA and WNV IgM IFA: Used for presumptive characterization for additional agreement studies.

There was no human expert adjudication method described (e.g., 2+1, 3+1 consensus) for the test sets. The laboratory results themselves served as the reference standard.

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

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done.

This device is an Enzyme Linked Immunosorbent Assay (ELISA) for the qualitative detection of IgM antibodies, which means it is a laboratory diagnostic test. It is not an AI-powered device or an imaging interpretation system that would involve human readers or AI assistance in the way typically discussed in MRMC studies. The device itself performs the detection.

6. If a Standalone (i.e., Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, the performance study was a standalone (algorithm only) evaluation.

The PANBIO West Nile Virus IgM Capture ELISA is an in-vitro diagnostic device that directly produces a result (positive, equivocal, negative) based on the biochemical reaction. Its performance was evaluated by directly comparing its output to established reference laboratory methods (PRNT, CDC MAC EIA, IgM IFA). There is no "human-in-the-loop" component in the sense of a human interpreting the device's output to make a primary diagnosis; the output is the diagnostic aid.

7. The Type of Ground Truth Used

The ground truth used in the performance studies was primarily laboratory reference assays:

• Plaque Reduction Neutralization Test (PRNT): Considered the gold standard for WNV confirmation.
• CDC MAC EIA (ELISA): Another established laboratory assay for WNV IgM detection.
• WNV IgM IFA (Immunofluorescence Assay): Another laboratory assay for WNV IgM detection.

For the cross-reactivity study, the ground truth was based on specimens from patients with confirmed diseases other than WNV.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" in the context of device development. This is typical for traditional ELISA-based diagnostic kits, where the assay principles and reagents are developed and optimized rather than "trained" in the machine learning sense. The performance characteristics are then verified using independent test sets as described.

9. How the Ground Truth for the Training Set Was Established

Since a "training set" (as understood in machine learning/AI) is not typically applicable to this type of device, the concept of establishing ground truth for it is also not relevant here. The device's components and parameters are likely optimized through laboratory R&D processes based on known positive and negative controls.

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The Epstein-Barr Virus Viral Capsid-p18 Antigen (EBV VCA-p18) IgG ELISA is for the qualitative detection of IgG antibodies to EBV VCA in serum as an aid in the clinical laboratory diagnosis of EBV infection in patients with clinical symptoms consistent with infectious mononucleosis (IM). The PANBIO EBV VCA-p18 IgG ELISA should be used in conjunction with other EBV serologies.

The EBV VCA-p18 IgG ELISA is an Enzyme Linked Immunosorbent Assay for the qualitative detection of IgG antibodies in human serum to EBV VCA antigen.

Here's a summary of the acceptance criteria and the study details for the PANBIO EBV VCA-p18 IgG ELISA, based on the provided text:

1. Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria in terms of numerical thresholds for sensitivity, specificity, or agreement. Instead, it presents the performance characteristics as a comparison to an equivalent device (DiaSorin EBV VCA IgG ELISA) and established EBV serological status. The study aims to demonstrate that the device performs comparably and effectively identifies different EBV infection states.

However, based on the results and the context of a 510(k) submission, we can infer that the observed performance values for sensitivity, specificity, and agreement, particularly in relation to the predicate device and the known EBV status, were considered acceptable by the manufacturer for regulatory clearance.

Table of Reported Device Performance for PANBIO EBV VCA-p18 IgG ELISA (Study Site 1):

Table of Reported Device Performance for PANBIO EBV VCA-p18 IgG ELISA (Study Site 3):

2. Sample Sizes and Data Provenance

Study Site 1 (Primary Performance Study):

• Sample Size (Test Set): 342 sera
  • Seronegative: 45
  • Acute IM: 41
  • Past Exposure to EBV: 256
• Data Provenance: Prospective sera collected from a private pathology laboratory in Queensland, Australia.

Study Site 3 (Confirmatory Performance Study):

• Sample Size (Test Set): 148 sera
  • Seronegative: 25
  • Acute IM: 23
  • Past Exposure to EBV: 100
• Data Provenance: Frozen retrospective sera submitted to a state health laboratory in Maryland, USA.

3. Number of Experts and their Qualifications (for Ground Truth)

The document does not explicitly mention the use of "experts" for establishing the ground truth in the traditional sense of clinicians or radiologists reviewing cases. Instead, the ground truth for the EBV status of the test sets was established by the results of other standard EBV serological assays.

The "EBV Status" was defined based on a combination of different assay results:

• Seronegative: VCA IgG (-), VCA IgM (-), EBNA IgG (-)
• Acute IM: VCA IgM (+), EBNA IgG (-)
• Past Infection: VCA IgG (+), VCA IgM (-), EBNA IgG (+)

This implies that the "experts" were the laboratory personnel and clinicians who interpreted these existing serological results to categorize the samples. No specific number or qualifications for individual experts interpreting these criteria are provided.

4. Adjudication Method

The document does not describe an adjudication method in the context of multiple expert readers. The ground truth was established by comparing the device's results to the serological EBV status determined by a panel of other EBV serologies. For the study at Site 3, it is noted that re-testing of equivocal samples was not conducted because the samples were unavailable. This suggests that there was no specific adjudication process for discordant results against the "EBV Status" ground truth, beyond the initial classification based on the serological panel.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. This study focuses on the standalone performance of an in vitro diagnostic device (ELISA) against serological ground truth and a predicate device, not on human reader performance with or without AI assistance.

6. Standalone (Algorithm Only) Performance

Yes, a standalone performance study (i.e., algorithm only without human-in-the-loop performance) was done. The PANBIO EBV VCA-p18 IgG ELISA is an automated/semi-automated test that provides a quantitative result (absorbance) which is then interpreted qualitatively (Positive/Negative/Equivocal) based on a cut-off ratio. The reported sensitivity, specificity, and agreement values are for the device itself.

7. Type of Ground Truth Used

The ground truth used was expert consensus derived from other EBV serological assays. The "EBV Status" for each sample was determined by a panel of a priori defined serological markers for VCA IgG, VCA IgM, and EBNA IgG, which are established indicators of different stages of EBV infection.

The study explicitly states: "Note: "Serological" sensitivity and specificity refers to the comparison of the PANBIO assay results to that of other assays normally used to diagnose EBV associated IM. There was not an attempt to correlate the assay's results with disease presence or absence. No judgement can be made on the comparison's accuracy to predict disease." This clarifies that the ground truth is based on laboratory-defined serological status, not direct clinical outcomes or pathology reports.

8. Sample Size for the Training Set

The document does not provide information about a distinct "training set." The studies described are performance evaluations of the finalized device (test sets). For an ELISA, development typically involves optimization using a set of samples, but these are not explicitly called out as a "training set" with specific numbers.

9. How Ground Truth for the Training Set Was Established

As no specific training set is detailed, information on how its ground truth was established is not provided. Typically, in the development of such assays, candidate samples would be characterized using established reference methods for the target analyte (EBV VCA IgG antibodies).

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