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The Access Intact PTH assay is a paramagnetic particle, chemiluminescent immunoassay for the quantitative determination of intact parathyroid hormone (parathyrin, PTH) levels in human serum and plasma using the Access Immunoassay Systems. It is indicated to aid in the differential diagnosis of hyperparathyroidism, hypoparathyroidism, or hypercalcemia of malignancy and can be used intraoperatively. Assay results should be used in conjunction with other clinical data to assist the clinician in making individual patient management decisions.

The Access Intact PTH assay is a sandwich immunoenzymatic assay. The Access Intact PTH assay consists of the reagent pack and calibrators. Other items needed to run the assay include substrate and wash buffers. The Access intact PTH assay reagent pack, Access intact PTH assay calibrators, along with the Access wash buffer and substrate are designed for use on the Dxl 9000 Access Immunoassay Analyzers in a clinical laboratory setting.

The provided text describes the performance validation of the Beckman Coulter Access Intact PTH assay on the Dxl 9000 Access Immunoassay Analyzer. This is a biomedical measurement device, specifically an in vitro diagnostic (IVD) rather than an AI-powered system as might be initially implied by the format of the request. Therefore, some of the requested information regarding AI-specific criteria (like number of experts for ground truth, adjudication methods, MRMC studies, training set details) is not applicable to this type of device.

Here's an analysis of the acceptance criteria and study results, focusing on the relevant aspects for an IVD device:

Acceptance Criteria and Reported Device Performance

The study primarily focuses on demonstrating the performance characteristics of the Access Intact PTH assay run on the Dxl 9000 system, compared to its predicate device (Access Intact PTH on the Access 2 Immunoassay System). The "acceptance criteria" here are performance targets related to analytical precision, linearity, and detection/quantitation limits, based on standard laboratory guidelines (CLSI documents).

Table of Acceptance Criteria and Reported Device Performance:

Notes on Performance:

• For Imprecision, one sample in the "Intraoperative Mode" (Sample 1, 1.7 pg/mL) shows a %CV of 13.2%, which exceeds the general criteria of "≤ 8.0% CV at concentrations > 12 pg/mL (1.3 pmol/L)" and also "≤ 0.96 pg/mL (0.10 pmol/L) SD at concentrations ≤ 12 pg/mL (1.3 pmol/L)". However, given the actual concentration and the stated SD for this sample (0.23 pg/mL), it might be acceptable for very low concentrations where relative variability can be higher, or it might fall into a specific acceptance sub-criterion not fully detailed here. The SD of 0.23 pg/mL is still well below the 0.96 pg/mL SD target for concentrations ≤ 12 pg/mL.
• The correlation coefficients (R) of 1.00 and 0.99 for method comparison indicate excellent agreement with the predicate device. The slopes and intercepts also demonstrate good agreement, supporting the claim of substantial equivalence.

Study Details:

As this is a 510(k) submission for an in vitro diagnostic immunoassay system, the concept of AI-driven image analysis or clinical decision support is not applicable. Therefore, many of the questions related to AI-specific validation (e.g., number of experts, adjudication, MRMC studies, AI training sets) are not relevant to this document. The "ground truth" for an IVD refers to the true concentration of an analyte as measured by a reference method or established through rigorous characterization of control materials.

1. Sample sizes used for the test set and data provenance:

   • Imprecision Study:
     • Routine Mode: 86 replicates for most samples (one sample with 84 replicates).
     • Intraoperative Mode: 88 replicates for all samples.
     • Data Provenance: Not explicitly stated, but typically these studies are conducted in a controlled laboratory setting (prospective data collection from prepared samples/controls). No country of origin for the data is specified, but given the manufacturer (Beckman Coulter, Inc., Chaska, MN, USA), it's highly likely to be US-based or from their global R&D facilities.
   • Method Comparison Study:
     • Routine Mode: N=144 patient samples.
     • Intraoperative Mode: N=116 patient samples.
     • Data Provenance: Not explicitly stated regarding country of origin or retrospective/prospective. These are typically patient plasma/serum samples collected prospectively for the study or from biobanks.

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

   • Not Applicable. This is an immunoassay device for quantitative determination of a hormone. The "ground truth" for these tests is based on the chemical measurement itself, validated against reference materials or established methods, not subjective expert interpretation of images or clinical data.

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

   • Not Applicable. See point 2.

4. 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:

   • Not Applicable. This is an automated immunoassay system, not an AI-assisted diagnostic tool requiring human reader interpretation studies.

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

   • This entire validation represents the "standalone" performance of the analytical instrument and assay kit. The Dxl 9000 Access Immunoassay Analyzer functions largely as an automated "algorithm" in that it processes samples and produces quantitative results without direct human interpretive input during the measurement process. Human oversight and quality control are part of its real-world use.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

   • The "ground truth" for this immunoassay is likely established through:
     • Reference Materials/Calibrators: These are materials with precisely known concentrations of intact PTH, used to calibrate the instrument and verify accuracy.
     • Predicate Device Comparison: The "Method Comparison" study uses the results from the legally marketed predicate device (Access Intact PTH on the Access 2 Immunoassay System) as the comparative reference, implicitly relying on the established accuracy of that predicate.
     • Analytical Standards: Performance metrics (LoB, LoD, LoQ, linearity) are assessed against internationally recognized analytical standards, such as those from CLSI (Clinical and Laboratory Standards Institute), which define the statistical and experimental methods for confirming these basic analytical performance parameters.

7. The sample size for the training set:

   • Not Applicable. This is an immunoassay device, not an AI/machine learning model that requires a "training set" in the conventional sense. The "training" of the device involves calibration using specified calibrator materials and internal quality control procedures.

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

   • Not Applicable. See point 7.

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The Access Intact PTH assay is a paramagnetic particle, chemiluminescent immunoassay for the quantitative determination of intact parathyroid hormone (parathyrin, PTH) levels in human serum and plasma using the Access Immunoassay Systems. It is indicated to aid in the differential diagnosis of hyperparathyroidism, hypoparathyroidism, or hypercalcemia of malignancy and can be used intraoperatively. Assay results should be used in conjunction with other clinical data to assist the clinician in making individual patient management decisions.

The Access Intact PTH Calibrators are intended to calibrate the Access Intact PTH assay for the quantitative determination of intact parathyroid hormone (parathyrin, PTH) levels in human serum and plasma using the Access Immunoassay Systems.

The Access Intact PTH reagents, calibrators, and the Access Immunoassay Analyzers (Access, Access 2, Synchron LXi 725, UniCel DxC600i, and UniCel Dxl 800) comprise the Access Immunoassay Systems for the determination of intact parathyroid hormone (PTH) levels in human serum and plasma.

Here's a breakdown of the acceptance criteria and study information for the Access Intact PTH and Intact PTH Calibrators on the Access® Immunoassay Systems, based on the provided 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

Note: The acceptance criteria are "implied" as specific thresholds were not explicitly stated in the 510(k) summary (e.g., "CV must be < X%"). The reported performance implicitly met the FDA's requirements for substantial equivalence.

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

• Imprecision: Not explicitly stated, but concentrations ranged from 12 to 1400 pg/mL, suggesting multiple samples tested at different levels.
• Dilution Recovery (Linearity): "Multiple dilutions of EDTA plasma samples" were analyzed. Specific number not provided.
• Methods Comparison:
  • Routine vs. Commercial Immunoassay: 500 values
  • Routine vs. Intraoperative: 493 values
  • Intraoperative vs. Commercial Immunoassay: 393 values
• Analytical Specificity: Not explicitly stated, but tested for potential contaminants (bilirubin, hemoglobin, human serum albumin, and triglycerides).
• Clinical Reference Range: 289 matched human EDTA plasma and serum samples.
• Data Provenance: The document does not explicitly state the country of origin.
  • For the clinical reference range, samples were collected during three time periods in two geographic latitudes, suggesting prospective collection for that specific study. Other analytical studies do not specify prospective or retrospective.

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

Not applicable. This is an in vitro diagnostic (IVD) device for quantitative measurement of a biomarker. The "ground truth" for the test set is established by the analytical method itself (e.g., reference method for comparison, known concentrations for dilution linearity, established analytical techniques for specificity and imprecision). No human experts are used to establish ground truth in the way they would for image interpretation or disease diagnosis. For the reference range study, specific criteria (normal serum calcium, creatinine, 25-hydroxyvitamin D) were used to select "apparently healthy" individuals, but the "ground truth" is the measured PTH level.

4. Adjudication method for the test set

Not applicable. As described above, this is an IVD device measuring a quantitative biomarker. Adjudication methods like 2+1 or 3+1 are typically used in studies involving subjective interpretation, such as imaging.

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

Not applicable. This is an IVD assay. It does not involve human readers interpreting cases with or without AI assistance. The comparisons done were between the new device and predicate devices.

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

Yes, the studies described are for the standalone performance of the Access Intact PTH assay on the Access Immunoassay Systems. The device produces a quantitative measurement of PTH levels. Human involvement is limited to operating the instrument and interpreting the numerical result in a clinical context, not in directly improving the "algorithm's" performance.

7. The type of ground truth used

• Imprecision & Dilution Recovery: The ground truth is the expected performance based on established analytical chemistry principles and the known characteristics of the samples (e.g., known concentrations, dilution factors).
• Methods Comparison: The ground truth is the measurement obtained from a commercially available, legally marketed immunoassay system (predicate device).
• Analytical Specificity: The ground truth is the known concentration of PTH in samples intentionally spiked with potential interferents.
• Clinical Reference Range: The "ground truth" is the distribution of PTH levels in a rigorously selected population of "apparently healthy" individuals, with exclusion criteria based on other clinical markers (serum calcium, creatinine, 25-hydroxyvitamin D).

8. The sample size for the training set

Not applicable in the context of typical AI/ML device development. This is an IVD device developed using traditional analytical chemistry and immunoassay principles, not a machine learning algorithm that requires a "training set" in the same way. The development and optimization of the assay would involve various experiments and reagent formulations, but these are not referred to as "training sets" in the ML sense.

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

Not applicable for the reasons stated in point 8.

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