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The Atellica® IM Total hCG (ThCG) assay is for in vitro diagnostic use in the quantitative determination of human chorionic gonadotropin (hCG) in human serum or plasma (EDTA or lithium heparin) using the Atellica® IM Analyzer.

Human chorionic gonadotropin measurements are intended for use as an aid in the early detection of pregnancy.

The Atellica® IM Total hCG (ThCG) Assay reagents come in the following configurations:
1 ReadyPack primary reagent pack containing Atellica IM ThCG Lite Reagent and Solid Phase Atellica IM ThCG master curve and test definition (90 Tests)
5 ReadyPack primary reagent packs containing Atellica IM ThCG Lite Reagent and Solid Phase Atellica IM ThCG master curve and test definition (450 Tests)

The ReadyPack consists of the following:
Atellica IM ThCG ReadyPack primary reagent pack Lite Reagent: 4.5 mL/reagent pack Goat polyclonal anti-hCG antibody (~0.1 µg/mL) labeled with acridinium ester in buffered saline; sodium azide (0.1%); preservatives
Solid Phase: 20.3 mL/reagent pack Mouse monoclonal anti-hCG antibody (~0.02 mg/mL) covalently coupled to paramagnetic particles in buffered saline; sodium azide (0.1%); preservatives.
Atellica IM ThCG DIL ReadyPack ancillary reagent pack: 25.0 mL/pack Buffered heat-treated equine serum; EDTA; sodium azide (< 0.1%); preservatives
Atellica IM ThCG DIL: 50.0 mL/vial Buffered heat-treated equine serum; EDTA; sodium azide (< 0.1%); preservatives

Here's a breakdown of the acceptance criteria and study information for the Atellica® IM Total hCG (ThCG) device, based on the provided FDA 510(k) summary:

The purpose of this submission (K192790) is to add a plasma (EDTA and lithium heparin) sample claim for the Atellica® IM Total hCG (ThCG) assay, which was previously cleared for serum samples under K172322. Therefore, the acceptance criteria and supporting studies specifically address the performance of the device with these new sample types.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for the new plasma sample types are implicitly derived from the established performance of the predicate device with serum and are demonstrated through equivalency studies. The key performance indicator for this submission is the agreement between plasma and serum samples.

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

• Sample Size for Specimen Equivalence (Test Set):

  • Dipotassium EDTA plasma: 116 samples
  • Lithium heparin plasma: 134 samples

• Sample Interval: 3.8 - 959.2 mIU/mL (IU/L) for both plasma types.

• Data Provenance: The document does not explicitly state the country of origin or whether the samples were retrospective or prospective.

• Sample Size for Interference (Test Set): Not explicitly stated, however, the results show bias at two analyte concentrations for each interferent, suggesting a controlled experimental setup, likely with replicates for each condition.

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

This type of immunoassay (quantitative determination of hCG) typically does not involve human experts establishing a subjective "ground truth" for individual test samples, as the analyte concentration is an objective biochemical measurement. The ground truth, in this context, is the measured hCG concentration in the serum samples, which essentially serves as the reference for comparison against plasma samples. The accuracy of these serum measurements would be ensured by laboratory quality controls and standardization against international reference materials (WHO 4th IS 75/589 reference material), as mentioned in the "Standardization" section. Therefore, no "experts" in the sense of clinical reviewers are used to establish ground truth for this type of quantitative assay performance study.

4. Adjudication Method for the Test Set

Not applicable. For a quantitative assay comparing different sample matrices, adjudication methods like N+1 consensus are not used. The comparison is statistical, based on linear regression and bias analysis between the results from the plasma samples and the reference serum samples.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done

No, an MRMC comparative effectiveness study was not done. This device is an in vitro diagnostic assay that quantitatively measures a biomarker (hCG). MRMC studies are typically performed for imaging devices or other diagnostic tools where human interpretation plays a role, to assess the impact of AI assistance on human reader performance. This submission focuses on the analytical performance of the assay itself with different sample types.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) was done

Yes, the performance studies described are standalone. The "device" in question is the Atellica® IM Total hCG (ThCG) assay, which is an automated in vitro diagnostic system. The performance data presented (specimen equivalence and interference) directly reflects the analytical performance of the assay when run on the Atellica® IM Analyzer, without human intervention in the measurement process itself, beyond standard laboratory procedures for sample handling and instrument operation.

7. The Type of Ground Truth Used

For the specimen equivalence study, the ground truth for comparison was the hCG concentration determined in human serum samples using the Atellica® IM Total hCG (ThCG) assay (the predicate device). The new sample types (EDTA plasma and lithium heparin plasma) were then tested on the same device and compared against these serum results.

For interference testing, the "ground truth" would be the expected hCG concentration in the samples without the interferent, or a known spiked concentration.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" in the context of this 510(k) submission. This is typical for in vitro diagnostic assays based on established immunoassay principles, where the assay design, calibration, and optimization (which can be analogous to "training" in AI/ML) would have been performed during the initial development and clearance of the predicate device (K172322). This submission is an extension of that device for new sample types, relying on the already established assay method.

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

As noted above, a distinct "training set" in the AI/ML sense is not directly applicable here. The "ground truth" for the development and establishment of the assay's performance would have involved:

• Standardization: Against the World Health Organization (WHO) 4th IS 75/589 reference material for hCG. This provides the fundamental "ground truth" reference for hCG concentration.
• Calibration: Assigned values for calibrators are traceable to this WHO standard.
• Analytical Performance Studies: Initial studies (precision, linearity, detection capability) performed for the predicate device (K172322) would have established the assay's performance characteristics against these standardized references and known concentrations.

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