Atellica® CH Creatinine_3 (Crea3)

• K Number: K242685
• Device Name: Atellica® CH Creatinine_3 (Crea3)
• Manufacturer: Siemens Healthcare Diagnostics Inc.
• Date Cleared: 2024-12-04 ( 89 days)
• Product Code: CGX
• Regulation Number: 862.1225
• Type: Traditional
• Panel: CH
• Reference & Predicate Devices: K161494

Intended Use

The Atellica® CH Creatinine_3 (Crea3) assay is for in vitro diagnostic use in the quantitative determination of creatinine in human serum, plasma (lithium heparin, dipotassium EDTA, and sodium heparin), and urine using the Atellica® CH Analyzer. Such measurements are used in the diagnosis and treatment of renal diseases, and in monitoring renal dialysis.

Device Description

The Atellica CH Crea3 assay is based on the reaction of picrate with creatinine in an alkaline medium to produce a red chromophore creatinine picrate complex. The rate of complex formation is measured at 505/571 nm and is proportional to the creatinine concentration. The Atellica CH Crea3 assay is a modification of the Jaffe method, using rate blanking and intercept correction. Rate blanking is used to minimize bilirubin interference. Also, because non-specific serum/plasma protein interactions with this reagent have been found to produce a positive bias of approximately 0.3 mg/dL (26.5 µmol/L), serum/plasma measurements are automatically corrected by subtracting 0.3 mg/dL (26.5 µmol/L) from each result.

AI/ML Overview

The provided text describes the performance characteristics and studies for the Atellica® CH Creatinine_3 (Crea3) assay, a new in vitro diagnostic device for quantitative determination of creatinine. It compares this new device to a predicate device, the Atellica® CH Creatinine_2 (Crea_2) assay.

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

Important Note: The document focuses on establishing substantial equivalence for an in vitro diagnostic (IVD) test, which primarily relies on analytical performance characteristics rather than clinical outcome studies or multi-reader multi-case (MRMC) comparative effectiveness studies typically seen with imaging AI devices. Therefore, some of your requested information (like number of experts for ground truth, adjudication methods, MRMC studies, and training set details for an AI model) are not directly applicable or provided in this type of submission.

---

Acceptance Criteria and Reported Device Performance

The acceptance criteria for this device are established through various analytical performance studies, primarily comparing it to a legally marketed predicate device (Atellica® CH Creatinine_2). The acceptance criteria are implicitly defined by the successful demonstration of equivalence or meeting pre-defined performance goals for each characteristic.

Here's a table summarizing the acceptance criteria (inferred from the "designed to have" or "determined in accordance with" statements and the reported results meeting these) and the reported device performance:

Performance Characteristic	Acceptance Criteria (Implicit)	Reported Device Performance (Atellica® CH Creatinine_3 (Crea3))
Detection Capability	LoB: $\le$ LoD for serum and urine samples.
LoD: $\le$ 0.15 mg/dL for serum/plasma; $\le$ 3.00 mg/dL for urine.
LoQ: $\le$ 0.15 mg/dL for serum/plasma with $\le$ 0.10 mg/dL total analytical error; $\le$ 3.00 mg/dL for urine with $\le$ 1.50 mg/dL total analytical error.	Serum/plasma:
LoB: 0.05 mg/dL
LoD: 0.10 mg/dL
LoQ: 0.15 mg/dL
Urine:
LoB: 0.50 mg/dL
LoD: 1.00 mg/dL
LoQ: 3.00 mg/dL
(All results meet the stated design goals/acceptance criteria).
Precision	Determined in accordance with CLSI Document EP05-A3 (indicates adherence to specific statistical targets for repeatability and within-lab precision, implicitly accepted if within CLSI guidelines for the assay's use).	Serum Samples (n=80 each):

• Serum 1 (0.38 mg/dL): Repeatability SD 0.006, CV 1.6%; Within-Lab SD 0.012, CV 3.2%
• Serum 2 (0.73 mg/dL): Repeatability SD 0.023, CV 3.2%; Within-Lab SD 0.029, CV 4.0%
• Serum 3 (0.73 mg/dL): Repeatability SD 0.006, CV 0.8%; Within-Lab SD 0.019, CV 2.6%
• Serum 4 (1.18 mg/dL): Repeatability SD 0.007, CV 0.6%; Within-Lab SD 0.019, CV 1.6%
• Serum QC 1 (1.85 mg/dL): Repeatability SD 0.007, CV 0.4%; Within-Lab SD 0.024, CV 1.3%
• Serum QC 2 (6.21 mg/dL): Repeatability SD 0.011, CV 0.2%; Within-Lab SD 0.067, CV 1.1%
• Serum 5 (17.39 mg/dL): Repeatability SD 0.035, CV 0.2%; Within-Lab SD 0.189, CV 1.1%
• Serum 6 (28.54 mg/dL): Repeatability SD 0.056, CV 0.2%; Within-Lab SD 0.317, CV 1.1%
  Urine Samples (n=80 each):
• Urine 1 (56.74 mg/dL): Repeatability SD 0.102, CV 0.2%; Within-Lab SD 0.746, CV 1.3%
• Urine 2 (135.80 mg/dL): Repeatability SD 0.206, CV 0.2%; Within-Lab SD 1.601, CV 1.2%
• Urine QC 1 (195.79 mg/dL): Repeatability SD 0.253, CV 0.1%; Within-Lab SD 2.376, CV 1.2%
  (All results demonstrate low CVs, indicating good precision). |
  | Reproducibility | Determined in accordance with CLSI Document EP05-A3 (implies meeting specific statistical targets for variability components across different days, lots, and instruments). | Serum Samples (n=225 each): Overall CV (%) for reproducibility ranges from 1.0% to 5.0%.
  Urine Samples (n=225 each): Overall CV (%) for reproducibility ranges from 1.4% to 1.6%.
  (All results demonstrate good reproducibility across conditions). |
  | Assay Comparison | Serum: Correlation coefficient $\ge$ 0.950 and slope of 1.00 ± 0.05, compared to predicate (Atellica CH Creatinine 2), using Weighted Deming regression.
  Urine: Correlation coefficient $\ge$ 0.950 and slope of 0.000 ± 3.00, compared to predicate (Atellica CH Creatinine 2), using Weighted Deming regression. | Serum (n=151): Regression equation y = 1.00x - 0.04 mg/dL, correlation coefficient (r) = 1.000. Sample range 0.44 to 28.64 mg/dL.
  Urine (n=113): Regression equation y = 1.00x + 0.14 mg/dL, correlation coefficient (r) = 1.000. Sample range 12.60 to 237.06 mg/dL.
  (Both serum and urine results meet the acceptance criteria for correlation and slope). |
  | Specimen Equivalence | Determined using Weighted Deming regression (implicitly, the regression line should demonstrate equivalence, i.e., close to y=x, with high correlation coefficient). | Sodium Heparin (n=50): y = 1.00x + 0.00 mg/dL, r=0.999.
  Lithium Heparin (n=50): y = 0.99x + 0.06 mg/dL, r=0.999.
  Dipotassium EDTA (n=50): y = 0.98x + 0.04 mg/dL, r=0.998.
  (All demonstrate strong equivalence to serum reference). |
  | Interferences (HIL) | $\le$ 10% interference from hemoglobin, bilirubin, and lipemia. Bias > 10% or 0.15 mg/dL (whichever is greater for serum/plasma) is considered interference. | Reported biases for Hemoglobin (1000 mg/dL), Conjugated Bilirubin (40-45 mg/dL), Unconjugated Bilirubin (45-60 mg/dL), and Lipemia (2250-3000 mg/dL) are all within the ±10% or ±0.15 mg/dL threshold for the tested analyte concentrations, demonstrating acceptable interference profiles. |
  | Interfering Substances | Bias $\le$ 10% or ±0.15 mg/dL for Serum/plasma samples. Bias $\le$ 10% for Urine samples (for listed substances). | Most tested substances (e.g., Acetaminophen, Ascorbic Acid, etc.) show negligible bias, meeting the criteria.

Substances showing bias beyond acceptance criteria for Serum:

• Cefoxitin: Significant interference (e.g., 243.6% and 947.9% bias at high concentrations).
• Cephalothin: Shows significant bias (e.g., 44.0% bias at 180 mg/dL).
• Glucose: Shows bias beyond 10% at higher concentrations (e.g., 11.5% at 500 mg/dL and 22.5% at 1000 mg/dL).
• Total Protein: Shows bias beyond 0.15 mg/dL at 15 g/dL (0.45 mg/dL).
• Acetohexamide: Shows bias beyond 10% at 2.0 mg/dL (10.4%).
• Hydroxocobalamin (Cyanokit): Shows significant bias (e.g., 14.5% and 49.3% at higher concentrations).

Substances showing bias beyond acceptance criteria for Urine:

• Cefoxitin: Shows bias beyond 10% at higher concentrations (e.g., 11.3% and 15.4%).
  (The document explicitly lists these substances under "Interference beyond ±10% for Serum" and "Interference beyond ±10% for Urine," indicating that they failed the non-interference criteria at the tested concentrations. This is typical for IVD submissions, where known interferences are identified for labeling purposes). |
  | Standardization | The assay shall be traceable to the reference material SRM967, from the National Institute of Standards and Technology (NIST). | Statement confirms the assay is traceable to NIST SRM967. |

---

Study Details:

1. Sample Size and Data Provenance:

   • Test Set Sample Sizes:
     • Detection Capability: Not explicitly stated as "sample size" but data points obtained according to CLSI EP17-A2.
     • Precision: 80 data points per serum/urine sample type (duplicate runs for 20 days, 2 runs/day).
     • Reproducibility: 225 data points per serum/urine sample type (n=5 in 1 run for 5 days using 3 instruments and 3 reagent lots).
     • Assay Comparison: 151 serum samples and 113 urine samples.
     • Specimen Equivalence: 50 samples for each plasma type (Sodium Heparin, Lithium Heparin, Dipotassium EDTA) compared to serum.
     • Interference (HIL & Non-Interfering Substances): Not explicitly stated as a total sample size, but experiments are designed to test specific analyte concentrations with and without interferents, following CLSI EP07-ED3.
   • Data Provenance: Not explicitly stated in terms of country of origin. Given the manufacturer (Siemens Healthcare Diagnostics Inc. in Tarrytown, New York, USA) and FDA submission, it's highly probable the studies were conducted in the US or in compliance with US regulatory standards. The studies described are retrospective in the sense that they use pre-collected or prepared samples to assess the analytical performance of the device under controlled conditions, not prospective in tracking patient outcomes in a clinical trial.

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

   • For an in vitro diagnostic (IVD) device measuring a quantitative analyte like creatinine, "ground truth" is typically established by reference methods or established laboratory standards and calibrators, not by human expert consensus or labeling of medical images.
   • The "ground truth" for creatinine concentration in this context is based on traceable reference materials (NIST SRM 967) and established laboratory measurement principles, and the performance is compared against a legally marketed predicate device.
   • Therefore, this question (relevant for AI/imaging devices) does not directly apply to this type of IVD submission.

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

   • Not applicable. Adjudication methods are typically used in clinical trials or image labeling pipelines where there's human interpretation involved and a need to resolve disagreements among multiple readers; this is an analytical performance study of an IVD 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 not an AI/imaging device. It's an in vitro diagnostic assay.

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

   • This is an automated IVD assay performed on the Atellica® CH Analyzer. Its intended use is quantitative determination of creatinine. Therefore, the performance described (precision, accuracy, interference, etc.) is its standalone performance without a human in the loop for the analytical measurement itself, though a human still interacts with the instrument and interprets the results in a clinical context.

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

   • The primary "ground truth" for the Atellica® CH Creatinine_3 assay's performance is traceability to NIST SRM 967 (a certified reference material for creatinine) and comparison to a legally marketed predicate device (Atellica® CH Creatinine_2) using method comparison validated against CLSI guidelines. This is a form of analytical reference standard and comparative performance to an established method.

7. The sample size for the training set:

   • This device is an analytical chemistry assay, not a machine learning/AI algorithm that requires a "training set" in the computational sense. The "development" or "optimization" of the assay would involve various experimental data, but it's not codified as a "training set" for an algorithm.

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

   • Not applicable, as there is no "training set" in the AI/ML context for this type of device. The assay development would rely on scientific principles of analytical chemistry, reagent formulation, and instrument calibration against known standards.

Regulation Number and Section

§ 862.1225 Creatinine test system.

(a)
Identification. A creatinine test system is a device intended to measure creatinine levels in plasma and urine. Creatinine measurements are used in the diagnosis and treatment of renal diseases, in monitoring renal dialysis, and as a calculation basis for measuring other urine analytes.(b)
Classification. Class II.