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The Albumin BCP2 assay is used for the quantitation of albumin in human serum or plasma on the ARCHITECT c System.

The Albumin BCP2 assay is to be used as an aid in the diagnosis and treatment of numerous diseases involving primarily the liver or kidneys.

The Albumin BCP2 assay is an automated clinical chemistry assay. The Albumin BCP2 procedure is based on the binding of bromocresol purple specifically with human albumin to produce a colored complex. The absorbance of the complex at 604 nm is directly proportional to the albumin concentration in the sample.

Methodology: Colorimetric (Bromocresol Purple)

This document is a 510(k) premarket notification for a new in vitro diagnostic device, the Albumin BCP2 assay, which measures albumin in human serum or plasma. It seeks to prove substantial equivalence to a predicate device, Albumin BCP.

Here's an analysis of the acceptance criteria and study that proves the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly present a formal "acceptance criteria" table with pass/fail thresholds for each performance characteristic. Instead, it describes various studies conducted and reports the results, implying that meeting standard analytical performance metrics demonstrates acceptable performance and substantial equivalence.

However, we can infer the acceptance criteria from the reported performance and the context of typical FDA 510(k) submissions for in vitro diagnostic assays. The studies are designed to demonstrate the new device performs comparably to established standards and the predicate device.

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

The document describes test methods rather than specific "test sets" in the context of an AI/ML algorithm that might have a dedicated validation dataset. Instead, for an in-vitro diagnostic device, studies are conducted across various analytical performance characteristics.

• Precision Study: "2 controls and 3 human serum panels were tested in duplicate, twice per day on 20 days on 3 reagent lot/calibrator lot/instrument combinations." This means 80 data points for each control/panel (2 tests/day * 20 days * 2 replicates).
• Accuracy Study: "2 lots of the Albumin BCP2 reagent, 2 lots of the Consolidated Chemistry Calibrator, and 1 instrument." (No specific sample count for patient samples, but implied to be sufficient for bias estimation against a reference material).
• Lower Limits of Measurement: "n ≥ 60 replicates of zero-analyte samples" for LoB, and "n ≥ 60 replicates of low-analyte level samples" for LoD and LoQ.
• Linearity: No specific sample size mentioned, but typically involves preparing multiple dilutions.
• Interference Study: "Each substance was tested at 2 levels of the analyte (approximately 3.5 g/dL and 5.0 g/dL)."
• Method Comparison: 127 serum samples.
• Tube Type: "Samples were collected from a minimum of 40 donors".
• Dilution Verification: 5 human serum samples prepared by spiking.

Data Provenance: The document doesn't explicitly state the country of origin for the human samples used in the studies. Given that Abbott Ireland Diagnostics Division submitted the application, the studies were likely conducted in a setting compliant with international standards, possibly in Ireland or the US given the FDA submission. The studies described are nonclinical laboratory studies, not human clinical trials. They are retrospective or prospective in the sense of laboratory-controlled experiments designed to evaluate performance characteristics.

3. Number of Experts Used to Establish Ground Truth and Qualifications:

This section is not applicable as this is an in-vitro diagnostic (IVD) device, specifically a clinical chemistry assay, not an AI/ML diagnostic software. The "ground truth" for an IVD device is established through:

• Reference Methods: Using highly accurate and precise laboratory methods (e.g., mass spectrometry, enzymatic methods, or other established validated assays) or certified reference materials (like ERM-DA470k/IFCC for accuracy testing).
• Standardization: Traceability to international standards (like IFCC).
• Analytical Performance: Rigorous testing against defined analytical parameters (precision, linearity, limits of detection/quantitation).

There is no "ground truth" derived from human expert consensus for this type of device.

4. Adjudication Method for the Test Set:

This is not applicable for the same reasons as #3. Adjudication methods (like 2+1, 3+1) are common in AI/ML studies where human readers are establishing ground truth for image interpretation or similar tasks. For an IVD assay, performance is judged against analytical accuracy and precision, not human consensus on results.

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

This is not applicable. MRMC studies are specific to AI/ML software that assists human readers (e.g., radiologists, pathologists) in interpreting medical images or data. This device is a quantitative laboratory assay. There is no human "reader" assisted by this device in the same way. The device directly measures a biochemical analyte.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance):

This isn't an "algorithm" in the AI/ML sense but rather a chemical assay method run on an automated analyzer. The entire performance data presented (precision, accuracy, linearity, interference, method comparison) represents the "standalone" analytical performance of the assay without human intervention influencing the measurement itself. Human involvement is in the operation of the instrument, quality control, and interpretation of the results, but not in the measurement process being evaluated here.

7. Type of Ground Truth Used:

The ground truth for this chemical assay is primarily established by:

• Standard Reference Materials (SRMs): For accuracy, the device's results are compared against ERM-DA470k/IFCC, which are certified reference materials with highly accurate assigned values.
• Reference Measurement Procedures: Implied by the use of standard methods and CLSI (Clinical and Laboratory Standards Institute) guidance, which dictates how analytical performance (e.g., LoB, LoD, LoQ, linearity, precision) should be determined using robust statistical methods and replicates.
• Predicate Device Comparison: For method comparison, the "ground truth" (or comparative truth) is the performance of the legally marketed predicate device (Albumin BCP) on patient samples.

8. Sample Size for the Training Set:

This concept of a "training set" is specific to AI/ML models. For an IVD assay, calibration and internal method development (which could be analogous to "training") would involve various reagent lots, calibrators, and QC materials provided by the manufacturer. The document does not specify a "training set size" in the AI/ML context because the development of a chemical assay follows different principles.

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

Again, this is not applicable in the AI/ML sense. For chemical assays, the establishment of the assay (analogous to "training") involves:

• Reagent Formulation and Optimization: Developing the chemical reagents (Bromocresol Purple, buffers, etc.) to ensure proper reaction kinetics, stability, and specificity.
• Calibrator Assignment: Assigning accurate values to calibrator materials used by the assay, often traceable to international standards (like ERM-DA470/IFCC).
• Method Development on Platform: Optimizing the assay parameters (volumes, incubation times, temperatures, wavelength) on the specific ARCHITECT c System to achieve optimal performance.
• Internal Validation: Initial testing during development to ensure the assay performs as expected before formal verification and validation studies are conducted for regulatory submission. This internal validation would use similar principles of analytical testing as described in Section 8 (e.g., accuracy, precision, linearity using reference materials and pooled human samples).

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The Albumin BCP assay is an in vitro diagnostic test used for the determination of albumin in human serum or plasma. Albumin measurements are used in the diagnosis and treatment of numerous diseases primarily involving the liver or kidneys.

The assay is intended for professional use only.

For In Vitro Diagnostic use only.

Albumin BCP reagent is ready to use liquid reagent that is supplied in two configurations: fill volume 20 mL in a 20 mL wedge or 50 mL in a 50 mL wedge, 6 wedges/kit.

Here's the breakdown of the acceptance criteria and study information for the Albumin BCP device, based on the provided text:

Acceptance Criteria and Device Performance

Note regarding "Test Set" and "Training Set" terminology: For in vitro diagnostic assays measuring specific analytes, the concepts of "test set" and "training set" (as typically used in machine learning or image analysis) are not directly applicable in the same way. Instead, performance studies use different sample types (e.g., control materials, patient samples, spiked samples) to validate the analytical performance characteristics. The following answers reflect this distinction.

Study Details:

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

   • Limit of Blank (LoB): Not explicitly stated, but performed with three different reagent lots (F0390, F0391, F0480) and one calibrator lot (E0179). LoB is typically determined using replicate measurements of blank samples.
   • Limit of Detection (LoD): Not explicitly stated, but inferred to be similar to LoB determination as it also uses reagent and calibrator lots.
   • Limit of Quantitation (LoQ): Not explicitly stated, inferred to be similar to LoB/LoD determination.
   • Precision Study: 80 replicates per level for three different reagent lots (F0390, F0391, F0480) across three levels (26.26-26.62 g/L, 40.53-40.67 g/L, 49.96-50.47 g/L) using human serum. An additional lot (90228) used 88 replicates per level (19.10 g/L, 40.18 g/L, 51.33 g/L).
   • Intra Assay Precision Study: 20 replicates per level for three different reagent lots (F0390, F0391, F0480) across three levels (21.4-21.5 g/L, 35.6-35.8 g/L, 50.2-50.3 g/L) using human serum.
   • Linearity (Measuring Range): Three different reagent lots (F0390, F0391, F0480) were tested across specified ranges (e.g., 4.17 to 78.30 g/L). Number of distinct samples within these ranges not explicitly stated.
   • Endogenous Interferences Study: "2 aliquots of serum pool were prepared (Base and Test pool)" for two albumin concentrations (~35 g/L and ~50 g/L), with the test pool divided into 4 sub-aliquots and diluted. Specific number of interference samples not stated, but covered a range of dilution levels (100% down to 0%).
   • Reagent Stability: Four different lots (F0390, F0391, F0480, 90228) were evaluated across three different concentration levels.
   • Method Comparison: 128 serum samples, including 8 altered samples, covering the measuring interval 6.0 - 70 g/L.
   • Matrix Comparison: 77 paired plasma/serum samples, including 7 altered samples, covering the assay's range, for both Lithium-Heparin plasma and Potassium EDTA plasma.

   Data Provenance: The studies used human serum and plasma samples. The document does not explicitly state the country of origin of the data or whether the samples were collected retrospectively or prospectively. Given the context of a medical device submission, these would typically be from clinical laboratory settings.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience):

   This is an in vitro diagnostic (IVD) assay for measuring a biochemical analyte (albumin). The "ground truth" for such assays is established by the reference methods or highly characterized materials used to calibrate and validate the assay. It does not involve human experts interpreting images or diagnosing conditions, but rather relies on established analytical standards and predicate devices.

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

   Not applicable. Adjudication methods like 2+1 or 3+1 are used for subjective interpretations (e.g., image reading) where disagreement among experts might arise. For quantitative IVD assays, performance is assessed against defined analytical criteria and reference values.

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 device, not an AI-assisted diagnostic tool that would involve human readers.

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

   Yes, the performance studies described are for the standalone functioning of the Albumin BCP assay on the AU680 Automatic Analyzer. This is inherent to the nature of an in vitro diagnostic test, where the device performs the measurement independently.

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

   The "ground truth" for this IVD device is established through:

   • Reference materials and calibrators: Used to ensure accuracy and traceability of measurements (e.g., ERM-DA 470k/IFCC for standardization).
   • Predicate device measurements: The method comparison study used a legally marketed predicate device (Siemens ADVIA 2400, ADVIA® Chemistry Albumin BCP assay) as a comparative standard.
   • Analytical standards: Performance is measured against accepted analytical performance guidelines (e.g., CLSI documents EP17-A2, EP05-A3, EP15-A3, EP6-A, EP07-A2, EP09-A3) which define acceptable limits for various performance characteristics.
   • Known concentrations: For studies like LoB, LoD, LoQ, Precision, and Intra-Assay Precision, samples with known or characterized concentrations (e.g., control materials, spiked samples, serum pools) are used to assess the device's accuracy and reproducibility.

7. The sample size for the training set:

   Not applicable in the machine learning sense. The device is a chemical assay, not an algorithm trained on a dataset. Its analytical characteristics are inherently designed and validated through laboratory studies.

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

   Not applicable. As explained above, this device does not utilize a "training set" in the context of machine learning. The analytical methods and performance targets are established through scientific principles of chemistry and validated using established laboratory practices and reference standards.

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