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The LIAISON® N-TACT® PTH Gen II is an in vitro chemiluminescent immunoassay (CLIA) intended for the quantitative determination of intact human parathyroid hormone in serum, EDTA and Lithium Heparin plasma samples. Measurements of parathyroid hormone levels are used in the differential diagnosis of hypercalcemia and hypocalcemia resulting from disorders of calcium metabolism. The test is to be performed on the LIAISON® XL Analyzer.

The LIAISON® N-TACT® PTH Gen II Control Set is intended for use as assayed quality control samples to monitor the accuracy and precision of the DiaSorin LIAISON® N-TACT® PTH Gen II assay.

The LIAISON® N-TACT® PTH Gen II Calibration Verifiers are assayed quality control materials intended for the quantitative verification of calibration and reportable range of the LIAISON® N-TACT® PTH Gen II assay.

The LIAISON® N-TACT® PTH Gen II assay is a modified two-step, two-site sandwich assay that uses two goat polyclonal antibodies for capture and detection of intact PTH. Results are determined by a 2 point calibration conversion of the master curve to a working curve. The light signal is measured by a photomultiplier as relative light units (RLU) and is proportional to the concentration of intact PTH present in the calibrators, controls or samples.

LIAISON® N-TACT® PTH Gen II Control set contains:
2 levels controls containing 80% human plasma spiked with 1-84 PTH, and preservatives; 4 vials each level; lyophilized
The target concentration for control level 1 is 20 pg/mL. The target concentration for control Level 2 is 300 pg/mL.
The range of concentrations of each control is reported on the certificate of analysis provided with each LIAISON® N-TACT® PTH Gen II Control set.

LIAISON® N-TACT® PTH Gen II Calibration Verifier set contains:
4 levels containing 80% human plasma spiked with 1-84 PTH, with preservative, . 1 vial each level, lyophilized
The target concentration for cal verifier A is 10 pg/mL. The target concentration for cal verifier B is 150 pg/mL. The target concentration for cal verifier C is 650 pg/mL. The target concentration for cal verifier D is 1600 pg/mL.
The range of concentrations of each calibration verifier is reported on the certificate of analysis provided with each LIAISON® N-TACT® PTH Gen II Calibration Verifier set.

Here's an analysis of the acceptance criteria and study details for the LIAISON® N-TACT® PTH Gen II device based on the provided 510(k) summary:

Acceptance Criteria and Reported Device Performance

The 510(k) summary for the LIAISON® N-TACT® PTH Gen II primarily demonstrates substantial equivalence to a predicate device. As such, the "acceptance criteria" are generally implied by the performance of the predicate device and the demonstration that the new device performs comparably or better, meeting established clinical laboratory guidelines. Specific numeric acceptance criteria are not explicitly stated in a "PASS/FAIL" format for each performance characteristic, but rather the study results are presented to show satisfactory performance.

Here's a table summarizing the performance characteristics and their reported results, which implicitly serve as the demonstration of meeting acceptance:

Study Details for LIAISON® N-TACT® PTH Gen II

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

   • Method Comparison: 198 patient samples. The provenance is not explicitly stated as country of origin, but the reference range study mentions "northern and southern regions of the U.S.", suggesting US-based samples for some studies. The study is retrospective, utilizing existing patient samples.
   • Sample Matrix Comparison: 65 matched patient sets (EDTA plasma, serum, SST serum, and Lithium Heparin plasma). Data provenance is not explicitly stated beyond being "patient sets." Retrospective.
   • Reference Range: 125 apparently healthy adults aged 21-70 years from mixed ethnic backgrounds (32.5% dark-skinned, 66.7% light-skinned, 0.8% unknown) from the northern and southern regions of the U.S. This is a prospective or retrospective collection of samples for establishing a reference interval.
   • Precision: 7 frozen EDTA plasma samples (coded panel) and 2 lots of LIAISON® N-TACT® PTH Gen II controls (2 levels). Samples were tested on two lots of reagents. This is a controlled lab study, not involving patient data per se beyond the initial source of the plasma samples.
   • Linearity: One sample pool of each type: serum, SST serum, EDTA plasma, and Lithium Heparin plasma. These were diluted. Controlled lab study.
   • High Dose Hook Effect: A zero sample spiked with PTH. Controlled lab study.
   • Recovery Study: 5 high concentration EDTA plasma samples and 5 low concentration EDTA plasma samples. Controlled lab study, not directly patient data.
   • Analytical Specificity (Cross-Reactivity & Interference): Samples spiked with specific substances. These are controlled lab studies.
   • Limit of Blank, Limit of Detection, Limit of Quantitation: Not explicitly stated, usually involves multiple replicates of blank and low-concentration samples. Controlled lab study.

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

   • This device is an in vitro diagnostic (IVD) immunoassay, not an image-based AI device. The "ground truth" is established through analytical methods and comparison to established, cleared diagnostic devices (predicate device) and clinical standards, rather than expert human interpretation.
   • For the method comparison, the "ground truth" for the test set is the result from the predicate device, Siemens ADVIA® CENTAUR INTACT Parathyroid Hormone (iPTH) Assay, which is an FDA-cleared device.
   • For other analytical performance studies (precision, linearity, recovery, etc.), the ground truth relies on carefully prepared samples with known concentrations or expected behaviors, measured against established analytical principles and validated laboratory methods. There are no "experts" establishing image-based ground truth here.

3. Adjudication method for the test set:

   • Not applicable as this is an IVD immunoassay, not a diagnostic imaging AI where human adjudication of ambiguous cases is typically required. The comparison is objective, numerical data between two analytical methods or against defined analytical targets.

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 IVD assay, not an AI-powered diagnostic imaging tool that assists human readers. The performance is assessed against a predicate device and analytical standards.

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

   • The LIAISON® N-TACT® PTH Gen II assay is a standalone device in the sense that it provides quantitative results for PTH concentration. It operates autonomously on the LIAISON® XL Analyzer without direct human interpretation of the result generation process. Interpretation of the PTH level in a clinical context (e.g., diagnosis of hyper/hypocalcemia) still involves human clinicians, but the device provides the raw measurement itself without human input into the measurement.

6. The type of ground truth used:

   • For Method Comparison: Results from the predicate device (Siemens ADVIA® CENTAUR INTACT PTH (iPTH) Assay, K020217).
   • For other analytical studies (Precision, Linearity, Recovery, etc.): Typically based on known concentrations of analytes in spiked samples or reference materials, or expected analytical behaviors according to established CLSI guidelines (e.g., EP5-A2 for Precision, EP6-A for Linearity, EP7-A2 for Interference, EP17-A2 for Detection Capability). For the reference range, it's derived from a healthy population cohort carefully selected using specific clinical criteria.

7. The sample size for the training set:

   • This document describes performance characteristics for an IVD kit, not an AI/Machine Learning model. Therefore, there isn't a "training set" in the sense of data used to train an algorithm. The development of the assay itself would involve internal optimization and validation, but these stages are not typically referred to as "training sets" in the context of conventional IVDs in 510(k) summaries.

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

   • As there is no "training set" in the AI/ML context, this question is not applicable. The assay's analytical characteristics are developed and verified through standard laboratory practices and comparison to reference methods, not through an iterative learning process with labeled data.

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The DiaSorin LIAISON® N-TACT® PTH Calibration Verifiers are assayed quality control materials intended for use in the quantitative verification of calibration and reportable range of the LIAISON® N-TACT® PTH Assay when performed on the LIAISON® Analyzer.

The LIAISON® N-TACT® PTH Calibration Verifiers consist of four levels. Each vial contains Iyophilized pooled human plasma spiked with PTH. The calibration verifiers are reconstituted with 2.0 mL of deionized or distilled water, allowed to sit for 10 minutes, and mixed gently before use. The calibration verifier set is provided with targeted PTH concentrations of 20, 150, 350 and 1500 pg/mL. The four levels were chosen to incorporate the range of the LIAISON® N-TACT® PTH Assay and to challenge the decision points of clinical importance for PTH.

The provided document describes a premarket notification for the DiaSorin LIAISON® N-TACT® PTH Calibration Verifiers. This device is an assayed quality control material, not an AI/ML powered device, and therefore the concepts of test sets, ground truth, expert adjudication, MRMC studies, or standalone performance do not apply. The document focuses on demonstrating substantial equivalence to a predicate device for regulatory clearance.

Here's an analysis based on the information provided, reinterpreting the "acceptance criteria" and "study" in the context of a quality control material seeking substantial equivalence:

1. Table of Acceptance Criteria and Reported Device Performance

For this type of device (calibration verifiers/quality control materials), the "acceptance criteria" revolve around demonstrating that the new device performs similarly to or meets the requirements for a quality control material and is substantially equivalent to an existing predicate device. The performance is assessed by comparing its characteristics and intended use to the predicate.

Study Proving Acceptance Criteria:

The "study" in this context is a substantial equivalence comparison to a legally marketed predicate device, the LIAISON® N-TACT® PTH Control Set (K033426). The provided text outlines this comparison, highlighting similarities and differences to demonstrate that the new device is as safe and effective as the predicate.

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

This concept is not applicable to this type of regulatory submission. There is no "test set" in the sense of patient data or algorithm performance evaluation. The "sample" here would refer to the characteristics of the calibration verifiers themselves, such as the different levels provided. The data provenance relates to the formulation of the human plasma, but not its origin in terms of "patient data."

• Sample Size: The device consists of four levels of calibration verifiers.
• Data Provenance: The matrix is "pooled human plasma." No specific country of origin or whether it's retrospective/prospective is detailed for the plasma source, as it's a raw material for a control.

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

This concept is not applicable. "Ground truth" in the context of AI/ML or diagnostic claim validation refers to an independent, highly accurate determination of a clinical condition. For a quality control material, the "truth" is the target concentration of PTH within the verifier, established during its manufacturing and assay. This is typically done through certified reference materials and established laboratory methods, not by clinical experts adjudicating cases.

4. Adjudication Method (e.g., 2+1, 3+1, none) for the Test Set

This concept is not applicable. There is no "adjudication" of patient cases or diagnostic outputs for a quality control material.

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 concept is not applicable. This device is a laboratory reagent (calibration verifier), not an AI-powered diagnostic tool used by human readers.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was Done

This concept is not applicable. This is a reagent, not an algorithm.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

The "ground truth" for the LIAISON® N-TACT® PTH Calibration Verifiers would be their assigned target PTH concentrations (20, 150, 350, 1500 pg/mL). These values are established during the manufacturing process using validated analytical methods and reference materials, ensuring the accuracy of the PTH concentration within each level of the verifier. It is not based on expert consensus, pathology, or outcomes data in a clinical sense, but rather on metrological traceability for an in-vitro diagnostic reagent.

8. The Sample Size for the Training Set

This concept is not applicable. There is no "training set" for this type of device.

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

This concept is not applicable. There is no "training set" or corresponding "ground truth" in the AI/ML sense.

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The LIAISON® N-tact™ PTH Assay is a chemiluminescent immunoassay to be used with the LIAISON® Analyzer for the quantitative determination of intact human parathyroid hormone in serum or EDTA plasma. Measurements of parathyroid hormone levels are used in the differential diagnosis of hypercalcemia and hypocalcemia resulting from disorders of calcium metabolism. Assay results should be used in conjunction with other clinical and laboratory data to assist the clinician in making individual patient management decisions.

The LIAISON® N-tact™ PTH Control Set is intended for use as an assayed quality control sample to monitor the accuracy and precision of the DiaSorin LIAISON® N-tact™ PTH immunoassay.

The method for quantitative determination of PTH is a direct, two site, sandwich type chemiluminescence immunoassay (CLIA). Affinity-purified antibody to the 39-84 amino acid sequence of PTH is coated to the solid phase. The second affinity-purified antibody to the 1-34 region is conjugated to an isoluminol derivative. During the incubation, PTH binds to the solid phase, and is subsequently bound by the isolumino! conjugated antibody. After the incubation, the unbound material is removed with a wash cycle. The starter reagents are then added and a flash chemiluminescent reaction is initiated. The light signal is measured by a photomultiplier as relative light units (RLU) and is proportional to the concentration of PTH present in calibrators, controls, or samples.

Here's an analysis of the DiaSorin LIAISON® N-tact™ PTH 510(k) Premarket Notification based on the provided text, focusing on acceptance criteria and study details:

The provided document describes a diagnostic device (immunoassay) for quantitative determination of human parathyroid hormone (PTH), not a device that involves AI or human-in-the-loop performance. Therefore, several sections of your request (e.g., number of experts, adjudication method, MRMC study, human readers, standalone performance, training set details) are not applicable to this type of device and study. The "acceptance criteria" here refer to analytical performance specifications for the assay.

Acceptance Criteria and Reported Device Performance

Study Details

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

   • Analytical Sensitivity: Determined from 3 lots of materials. Specific sample count not provided, but it would involve multiple measurements of zero-concentration samples.
   • Functional Sensitivity: Determined from serial dilution; specific sample count not provided.
   • Linearity of Dilution: Demonstrated using nineteen samples and four lots of materials.
   • Inter-assay Precision: Not explicitly stated how many samples were used, but performance was assessed over a concentration range of 35-1290 pg/mL, implying multiple samples at various concentrations.
   • Recovery: Assessed by spiking synthetic PTH into serum samples; specific sample count not provided.
   • Freeze/Thaw Stability: Not explicitly stated how many samples were used, but it involved comparing fresh samples with those subjected to 4 freeze/thaw cycles.
   • Carryover: Not explicitly stated how many samples were used, but it involved testing low concentration samples directly after high concentration samples.
   • Correlation with Predicate Device: Not explicitly stated how many samples were used for the comparison, but results state "the LIAISON® method correlated well with the predicate device (r = 0.992)".
   • Reference Ranges: Established from "a population of normal, apparently healthy volunteers" for the normal range. "Subjects with an established diagnosis of either hypoparathyroidism or hyperparathyroidism" were used for disease-specific ranges. Specific sample sizes for these populations are not provided.
   • Data Provenance: Not explicitly stated, but typical for such studies would be samples collected from a clinical laboratory setting, likely in the country of manufacturing/testing (USA, given the submission information). The studies are retrospective analyses of samples performed using the device.

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

   • Not Applicable: For an immunoassay, "ground truth" is established by the analytical properties of the reference materials and the chemical/biological properties of the analytes, not by expert consensus on visual assessment or interpretation. For reference ranges, the "ground truth" for disease states is based on an "established diagnosis," likely made by clinicians following standard medical protocols, but no specific number or qualification of experts is provided as this is a standard clinical practice.

3. Adjudication method for the test set:

   • Not Applicable: Adjudication methods (e.g., 2+1, 3+1) are relevant for subjective assessments, particularly in medical imaging studies where multiple readers interpret cases. This is an objective, quantitative laboratory assay.

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 in vitro diagnostic assay, not an AI-assisted diagnostic tool involving human readers.

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

   • Yes (for the analytical performance): The performance data presented (sensitivity, precision, linearity, recovery, etc.) represents the intrinsic analytical performance of the LIAISON® N-tact™ PTH Assay system (reagents + LIAISON® Analyzer) without any human interpretive overlay beyond standard laboratory procedures and result reporting. This is by nature "algorithm-only" in the context of an automated immunoassay.

6. The type of ground truth used:

   • Reference/Comparator Methods and Established Clinical Diagnoses:
     • For analytical performance (e.g., sensitivity, linearity, recovery): Ground truth is based on known concentrations of synthetic PTH or highly characterized reference materials.
     • For correlation: The predicate device (DPC Coat-A-Count® Intact PTH IRMA) served as a comparator, essentially a "ground truth" for comparative performance.
     • For reference ranges: "Established diagnosis of either hypoparathyroidism or hyperparathyroidism" served as the clinical ground truth for those populations, and "normal, apparently healthy volunteers" for the normal range.

7. The sample size for the training set:

   • Not Applicable/Not Explicitly Stated: Immunoassays like this are not "trained" in the machine learning sense. The device's calibration curve (based on 10 points/standards) could be considered analogous, which is established using known concentrations, but it's not a "training set" in the context of AI. The stability of the Master Curve stored on the system implies it's robustly established.

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

   • Not Applicable/Known Concentrations: For the instrument's calibration (Master Curve), the ground truth is established by using "serum based standards representing concentrations from 2.5 to 2000 pg/mL." These standards contain precisely known amounts of PTH, which are manufactured and verified.

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