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510(k) Data Aggregation
(164 days)
NAO
In vitro diagnostic for the quantitative determination of carbohydrate-deficient transferrin (CDT) in human serum by means of particle-enhanced immunonephelometry using the BN™ II and BN ProSpec® System. The N Latex CDT assay must be run concurrently with the N Antisera to Human Transferrin assay so that the result can be expressed as a relative ratio, i.e., %CDT of the total transferrin. The calculation of %CDT can be used as a tool to identify possible chronic heavy alcohol consumption.
The CDT in the sample competes with CDT-coated polystyrene particles for the bond to specific monoclonal antibodies against human CDT, which are likewise bound to polystyrene particles. In the presence of CDT in the sample, there is no or little aggregation of the polystyrene particles. In the absence of CDT in the sample, the polystyrene particles aggregate. The higher the CDT content in the assay, the lower the scattered light signal. The evaluation is performed by comparison with a standard of known concentration.
The provided text describes the 510(k) summary for the N Latex CDT Kit, which is an in vitro diagnostic device. The study presented focuses on demonstrating substantial equivalence to a legally marketed predicate device rather than defining and meeting new acceptance criteria for standalone performance or comparative effectiveness.
Here's an analysis based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance:
The document does not explicitly state "acceptance criteria" in the traditional sense of pre-defined thresholds for performance metrics. Instead, it demonstrates performance by comparing the new device (N Latex CDT assay) against a predicate device (Axis-Shield %CDT assay). The criteria for "acceptance" appear to be based on a high correlation and agreement with the predicate.
| Performance Metric | Acceptance Criteria (Implicit) | Reported Device Performance (N Latex CDT vs. Predicate) |
|---|---|---|
| Correlation | Close to 1.0 | Correlation coefficient: 0.99 |
| Agreement (Linear Regression) | Slope close to 1, Intercept close to 0 | y = 0.720x + 0.75 %CDT |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size for Test Set: 116 serum samples
- Data Provenance: The document does not specify the country of origin of the data or whether the study was retrospective or prospective. It only states that 116 serum samples were "evaluated."
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
Not applicable. The study does not establish "ground truth" through expert consensus. Instead, it uses a legally marketed predicate device's results as the reference for comparison.
4. Adjudication Method for the Test Set:
Not applicable. There was no expert adjudication process described, as the comparison was against a predicate device's results.
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 device is an in vitro diagnostic assay, not an AI-assisted diagnostic tool involving human readers. Therefore, an MRMC study or evaluation of human reader improvement with AI assistance is not relevant to this submission.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:
The device's performance, as described by the regression analysis (y = 0.720x + 0.75 %CDT, correlation coefficient 0.99), is essentially its "standalone" performance when compared against the predicate device. It's a chemical assay, so its performance is inherent to the assay itself.
7. The Type of Ground Truth Used:
The "ground truth" in this context is the results obtained from the predicate device (Axis-Shield %CDT Assay) for the same serum samples. This is a form of reference standard comparison rather than ground truth established by pathology or clinical outcomes.
8. The Sample Size for the Training Set:
Not applicable. This is an in vitro diagnostic assay, not a machine learning or AI-based device that typically requires a distinct training set in the same manner. The "training" of such a device generally refers to its chemical formulation and calibration, which is not detailed in terms of a "training set sample size" in this document.
9. How the Ground Truth for the Training Set Was Established:
Not applicable, as there is no mention or implication of a "training set" in the context of machine learning or AI. The development of an in vitro diagnostic largely relies on chemical and biological principles, calibration, and validation, rather than ground truth established for a training dataset in the AI sense.
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(58 days)
NAO
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(148 days)
NAO
The Axis ® %CDT Turbidimetric Immunoassay (TIA) is intended for the quantitative measurement of carbohydrate deficient transferrin (CDT) in human serum, as a tool to identify possible chronic heavy alcohol consumption.
The Axis ® %CDT Turbidimetric Immunoassay is designed for the quantitative determination of carbohydrate deficient transferrin (CDT) in human serum.
The Axis® %CDT is a heterogeneous immunoassay with column separation followed by turbidimetric measurement. Serum transferrin in the sample is saturated with Fe ". The mixture is applied to an ion-exchange column. Due to the different amounts of sialic residues on transferrin, the isoforms carry different charges and are separated in the column. The CDT isoforms are eluted. The CDT content of the collected eluate is determined by turbidimetric measurement.
The eluted CDT isoforms form immune complexes with anti-transferrin antibodies. Total transferrin content of the sample is determined separately, using the same anti- transferrin antibodies. The measurements are evaluated using a calibration curve, and the Axis® %CDT value is calculated.
The Axis® %CDT Turbidimetric Immunoassay (TIA) is designed for the quantitative determination of carbohydrate deficient transferrin (CDT) in serum to identify possible chronic heavy alcohol consumption.
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance | Comments |
|---|---|---|---|
| Clinical Performance (vs. GGT) | Sensitivity at 5% CDT cut-off | Males: 0.70 | |
| Females: 0.55 | Compared to Gamma-glutamyl transferase (GGT) | ||
| Specificity at 5% CDT cut-off | Males: 0.93 | ||
| Females: 0.91 | Compared to GGT | ||
| Correlation with GGT | Low and not significant | Consistent with literature | |
| Area Under the Curve (ROC) | Identical to GGT for all subjects (combined genders) | Suggests similar overall diagnostic accuracy | |
| AUC for Males | Slightly better for CDT than GGT | ||
| AUC for Females | Slightly better for GGT than CDT | ||
| Precision | Within-run CV (low control) | 4.8% | NCCLS document EP5-T2 followed |
| Within-run CV (high control) | 2.7% | ||
| Total Precision (low control) | 6.4% | ||
| Total Precision (high control) | 3.4% | ||
| Analytical Sensitivity | Limit of Detection (LOD) | 1.0 mg/L transferrin | |
| Limit of Quantification (LOQ) | 1.0 mg/L CDT and 1.5 mg/L total transferrin | ||
| Linearity | Measuring Range | 0 - 50 mg/mL | |
| Accuracy | Correlation with HPLC %CDT (r) | 0.96 | Comparison to a recognized gold standard |
| Slope vs. HPLC %CDT | 1.12 | ||
| Y-Intercept vs. HPLC %CDT | -0.15 | ||
| Interference | Hemoglobin interference | 10% for concentrations above 10g/L | Note: Interference observed at high lipid levels |
| Plasma vs. Serum | Significantly higher %CDT in plasma | Sample type impact | |
| Drug interference | No effect on CDT level | ||
| Hook effect (Total Transferrin) | Critical at > 100mg/L; no clinical consequence | Human TT values are far below this level | |
| Temperature Sensitivity | Low control %CDT (18°C, 25°C, 30.5°C) | 2.5%, 4.9%, 8.3% respectively | Indicates temperature dependence |
| High control %CDT (18°C, 25°C, 30.5°C) | 8.3%, 9.5%, 11.2% respectively | Indicates temperature dependence |
2. Sample Size Used for the Test Set and Data Provenance:
The document does not explicitly state the exact sample size for the test set used in study CT-C8001. It describes the study group as "social drinkers and in chronic heavy drinkers," differentiating between males and females in the performance analysis.
The data provenance is not explicitly stated in terms of country of origin. The study appears to be retrospective as it analyzes associations between CDT, GGT, and drinking habits.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
The document does not specify the number or qualifications of experts used to establish the ground truth for the test set.
4. Adjudication Method for the Test Set:
The document does not describe an adjudication method for the test set. The ground truth appears to be based on "social drinkers" vs. "chronic heavy drinkers" which would typically be established through self-reporting or clinical assessment, but the method for confirming these classifications is not detailed.
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 device is an in vitro diagnostic (IVD) immunoassay, not an AI-powered diagnostic imaging or interpretation tool designed to assist human readers. Therefore, an MRMC comparative effectiveness study involving human readers and AI assistance is not applicable and was not performed.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:
Yes, the study describes the standalone performance of the Axis® %CDT TIA. The reported sensitivities, specificities, and AUC values are for the device itself, not in conjunction with human interpretation or intervention for the actual measurement. The calculation of %CDT from measured concentrations is an intrinsic function of the assay.
7. The Type of Ground Truth Used:
The ground truth appears to be a clinical classification based on behavioral and lifestyle factors: "social drinkers" and "chronic heavy drinkers." While not specified, these classifications are typically established through patient history, questionnaires, or other clinical assessments rather than pathology or direct outcomes data provided within this summary.
8. The Sample Size for the Training Set:
The document does not explicitly mention a separate "training set" or its sample size. The description pertains to the overall clinical study (CT-C8001) which evaluates the device's performance in different drinking groups. It's possible the entire dataset was used for evaluation, or aspects of the assay development were done with internal data not detailed here.
9. How the Ground Truth for the Training Set Was Established:
As no explicit training set is mentioned, the method for establishing ground truth for a training set is not provided. If the clinical study data was also used for "training" or refinement, the ground truth would have been established by classifying individuals as "social drinkers" or "chronic heavy drinkers" as described above (likely based on self-reported alcohol intake or clinical assessment for drinking patterns).
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