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Immunoassay for the in vitro quantitative determination of digoxin in human serum and plasma. Measurements are used in the diagnosis and treatment of digoxin overlose and in monitoring levels of digoxin to ensure proper therapy. The electrochemiluminescence immunoassay "ECLIA" is intended for use on Elecsys and cobas e immunoassay analyzers.

The Elecsys Digoxin assay employs a competitive test principle using a monoclonal antibody specifically directed against digoxin. Digoxin in the sample competes with the added digoxin derivative labeled with biotin for the binding sites on the ruthenylated antibody-complex. Results are determined via a calibration curve which is instrument- specifically generated by 2point calibration and a master curve provided via the reagent barcode. The reagent working solutions include: RackPack (kit placed on instrument) M: Streptavidin-coated microparticles, R1: Anti digoxin AbRu(bpy) 3+ and R2: Digoxin-derivativebiotin. PreciControl Cardiac II is a lyophilized control serum based on human serum in two concentration ranges. The controls are used for monitoring the accuracy and precision of the Elecsys CK MB, CK MB STAT, Myoglobin, Myoglobin STAT, proBNP II, proBNP II STAT, and Digoxin immunoassays.

The provided document is a 510(k) summary for the Elecsys Digoxin Immunoassay and Elecsys PreciControl Cardiac II. It describes the device, its intended use, and various performance evaluations conducted.

Here's a breakdown of the requested information based on the provided text:

1. Table of acceptance criteria and the reported device performance

The document lists performance characteristics in a comparative table (Table 1 and Table 2) between the "Predicate Device Elecsys Digoxin Immunoassay (K973112)" and the "Candidate Device Elecsys Digoxin Immunoassay." While specific acceptance criteria are not explicitly stated for each test, the reported performance data for the candidate device can be listed. The comparison to the predicate device implies that the candidate device's performance should be equivalent or better.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

• Precision (Repeatability and Intermediate Precision):
  • Sample Size: A seven-member panel consisting of five pooled human serum samples (HS) spiked with digoxin and two controls (PCC II = PreciControl Cardiac II, Level 1 and 2).
  • Data Provenance: Not explicitly stated, but typically these samples are prepared in a laboratory setting. No country of origin is mentioned.
  • Type of Study: Prospective, as samples were measured over 21 operating days.
• Reproducibility:
  • Sample Size: 5 aliquots of each control (PCC II = PreciControl Cardiac II) and five serum sample pools spiked with digoxin.
  • Data Provenance: Not explicitly stated.
  • Type of Study: Prospective.
• Limit of Blank (LoB):
  • Sample Size: 5 blank samples. A total of n = 60 LoB measurements were made.
  • Data Provenance: Native human serum pools and Universal Diluent. Not explicitly stated.
  • Type of Study: Prospective.
• Limit of Detection (LoD):
  • Sample Size: 5 low-level human serum samples (diluted). A total of n = 60 LoD measurements were made.
  • Data Provenance: Not explicitly stated.
  • Type of Study: Prospective.
• Limit of Quantitation (LoQ):
  • Sample Size: A set of ten human serum samples.
  • Data Provenance: Not explicitly stated.
  • Type of Study: Prospective.
• Linearity:
  • Sample Size: A high analyte serum sample pool spiked with digoxin, diluted to create fifteen concentrations (13 dilutions).
  • Data Provenance: Not explicitly stated.
  • Type of Study: Prospective.
• Dilution:
  • Sample Size: Four human serum samples with Digoxin concentrations above the measuring range.
  • Data Provenance: Not explicitly stated.
  • Type of Study: Prospective.
• Human Anti-Mouse Antibodies (HAMA):
  • Sample Size: A high HAMA serum pool and another serum pool without HAMA, prepared with two different digoxin concentrations and 11 dilution steps for each.
  • Data Provenance: Not explicitly stated.
  • Type of Study: Prospective.
• Endogenous Interferences:
  • Sample Size: For each interfering substance, 3 serum samples containing low, mid, and high concentrations of digoxin were tested.
  • Data Provenance: Human serum samples spiked with digoxin. Not explicitly stated.
  • Type of Study: Prospective.
• Exogenous Interference – Drugs:
  • Sample Size: Sixteen pharmaceutical compounds and 17 special cardiac drug compounds spiked into two human serum samples (analyte concentrations approx 0.6 and 2.4 ng/mL).
  • Data Provenance: Human serum samples. Not explicitly stated.
  • Type of Study: Prospective.
• Exogenous Interferences – Anticoagulants:
  • Sample Size: Either 65 or 66 serum/plasma pairs per sample material (Serum, Li-Heparin, K2-EDTA-, and K3-EDTA-plasma, and Li-Heparin Plasma Separation Tubes).
  • Data Provenance: Single donors, native as well as spiked. Not explicitly stated.
  • Type of Study: Prospective.
• Analytical Specificity/Cross Reactivity:
  • Sample Size: Two human serum samples spiked with potential cross-reactant compounds (analyte concentrations approx 0.5 and 2.0 ng/mL).
  • Data Provenance: Not explicitly stated.
  • Type of Study: Prospective.
• Method Comparison:
  • Sample Size: 168 human serum samples.
  • Data Provenance: All single donors, native as well as spiked. Not explicitly stated.
  • Type of Study: Prospective.
• Reagent Stability:
  • Study 1 (After First Opening): Five human serum samples and two controls.
  • Study 2 (On-board): Four human serum samples and two controls.
  • Study 3 (Real-Time Shelf-Life): Seven human serum samples covering the measuring range.
  • Study 4 (Accelerated Stability): Five human serum samples and two controls.
  • Data Provenance (all stability studies): Human serum samples and controls. Not explicitly stated.
  • Type of Study: Prospective.
• Calibration Stability:
  • Study 1 (Lot Calibration): Four human serum (HS) samples and two control samples.
  • Study 2 (On-board): Five human serum samples and two controls.
  • Data Provenance (all stability studies): Human serum samples and controls. Not explicitly stated.
  • Type of Study: Prospective.
• Sample Stability:
  • Study 1 (2-8°C): Seven human samples for each sample type (Serum, K2-EDTA-, K3-EDTA- and Li-Heparin-plasma).
  • Study 2 (Room Temperature): Nine human samples for each sample type (Serum, K2-EDTA-, K3-EDTA- and Li-Heparin-plasma).
  • Study 3 (-20°C): Eight samples for each sample type (Serum, K2-EDTA-, K3-EDTA- and Li-Heparin-plasma).
  • Data Provenance (all sample stability studies): Single donors spiked with digoxin. Not explicitly stated.
  • Type of Study: Prospective.

3. 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 report does not involve medical imaging or clinical diagnosis by human experts to establish ground truth. The device is an in vitro diagnostic immunoassay that measures digoxin levels directly. The "ground truth" for method comparisons and analytical studies is established by reference methods, spiking known concentrations, or comparing to a legally marketed predicate device (K973112) that is already accepted as providing accurate measurements. No human expert consensus for "ground truth" is described or required for this type of device.

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

Not applicable. As this is an in vitro diagnostic device for quantitative determination of a biomarker, there is no "adjudication method" in the context of expert review or consensus for image or clinical assessment. The performance is evaluated analytically against established laboratory standards and methods (e.g., CLSI guidelines).

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 immunoassay, not an AI/imaging device that involves human readers or an MRMC study design.

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

Yes, the studies described are standalone performance evaluations of the Elecsys Digoxin Immunoassay. The device performs the quantitative measurement of digoxin, and its accuracy, precision, and other analytical characteristics are evaluated directly. There is no "human-in-the-loop" performance aspect for the primary function of the immunoassay itself in generating a quantitative result.

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

The "ground truth" for the performance evaluation of the Elecsys Digoxin Immunoassay is established through:

• Spiking known concentrations: For studies like linearity, LoB, LoD, LoQ, and interference studies, samples are often prepared by adding known amounts of digoxin or interfering substances to a matrix.
• Reference methods/Predicate device comparison: For method comparison studies, results are compared against a legally marketed predicate device (Elecsys Digoxin immunoassay (K973112)) which serves as the a reference for expected performance.
• ** gravimetric assignment:** For the Elecsys Digoxin CalSet, calibration standards are stated to be standardized by "weighing United States Pharmacopoeia (USP) digoxin reference material into analyte free human serum." This is a form of gravimetric ground truth.

8. The sample size for the training set

The provided document describes analytical performance studies and does not mention a "training set" in the context of machine learning. The Elecsys Digoxin Immunoassay employs an electrochemiluminescence immunoassay (ECLIA) with a competitive test principle, which is a biochemical method, not an AI method that requires a training set. Development of the immunoassay itself involved optimizing reagents and protocols, but not "training" in the AI sense.

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

Not applicable, as no training set for an AI model is described or used in the context of this immunoassay's performance evaluation.

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