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510(k) Data Aggregation
(59 days)
THERMO DMA FRUCTOSAMINE ASSAY, MODEL 7500-135/235
This reagent is intended for the in vitro quantitative determination of Fructosamine (glycated protein) in human serum when run on the Hitachi 704 automated chemistry analyzer. Measurements of fructosamine are used as an aid for short-term glycemic control related to diabetes management.
Thermo DMA's fructosamine reagent is intended for the in vitro quantitative determination of Fructosamine in human serum. Under alkaline conditions, analytes with Amadori rearrangements, such as Fructosamine, have reducing activity that can be differentiated from other reducing substances. In the presence of carbonate buffer, fructosamine rearranges to the eneaminol form, which reduces Nitroblue tetrazolium (NBT) to a formazan. The absorbance at 530 nm is measured at two time points and the absorbance change is proportional to the fructosamine concentration. A 10-minute incubation is employed to allow fast reacting interfering reducing substances to react. Removal of endogenous glucose is not required due to the fact that a pH of greater than 11 is required for glucose to reduce NBT.
Here's a breakdown of the acceptance criteria and study details for the Thermo DMA Fructosamine Assay, based on the provided text:
Thermo DMA Fructosamine Assay: Acceptance Criteria and Study Details
The provided document describes the Thermo DMA Fructosamine Assay, intended for the in vitro quantitative determination of Fructosamine in human serum. The study primarily focuses on demonstrating substantial equivalence to a predicate device (Sigma Diagnostics Fructosamine, Procedure No. 465) through method comparison and precision studies.
1. Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined acceptance criteria in a dedicated section. Instead, it presents performance data and then concludes that the device is "safe and effective" and that "No significant differences exist between the results obtained on samples analyzed utilizing the Thermo DMA Fructosamine when compared to those obtained when utilizing the predicate device in these studies."
Based on the presented data, the implicit acceptance criteria and the device's reported performance are summarized below:
| Performance Metric | Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|---|
| Method Comparison | Strong correlation with the predicate device, with a slope close to 1, an intercept close to 0, and a high correlation coefficient. | Number of Sample Pairs: 49 |
| Range of Sample Results: 1.25 - 5.10 mmol/L | ||
| Mean (Sigma): 2.17 | ||
| Mean (Thermo DMA): 2.17 | ||
| Slope: 0.980 | ||
| Intercept: 0.039 | ||
| Correlation Coefficient: 0.998 | ||
| Precision (Within Run) | Low Coefficient of Variation (CV%) | Level 1: Mean = 2.21 mmol/L, SD = 0.02 mmol/L, CV = 1.1% (N=20) |
| Level 2: Mean = 3.47 mmol/L, SD = 0.04 mmol/L, CV = 1.1% (N=20) | ||
| Precision (Total Run) | Low Coefficient of Variation (CV%) | Level 1: Mean = 2.21 mmol/L, SD = 0.04 mmol/L, CV = 1.6% (N=10) |
| Level 2: Mean = 3.42 mmol/L, SD = 0.04 mmol/L, CV = 1.2% (N=10) | ||
| Sensitivity | Ability to detect low concentrations of fructosamine. | Instrument Resolution: 0.02 mmol/L (based on A = 0.001) |
| Serial Dilution: 0.1 mmol/L (based on control material) | ||
| Reportable Range | Ability to accurately measure fructosamine over a clinically relevant range, encompassing both normal and elevated levels. | Observed Range (asymptomatic samples): 1.6 - 2.6 mmol/L (N=31) |
| Linearity: Demonstrated acceptable performance up to 6.0 mmol/L | ||
| Specificity (Bilirubin) | Absence of significant interference at clinically relevant bilirubin levels. | At 2.5 mmol/L fructosamine: Positive interference > 2.8 mg/dL bilirubin. |
| At 4.1 mmol/L fructosamine: Positive interference > 13.5 mg/dL bilirubin. (Suggests interference at higher bilirubin levels, implying an implicit acceptance of lower levels/consideration for clinical context) | ||
| Specificity (Hemoglobin) | Absence of significant interference at clinically relevant hemoglobin levels. | "Hemolyzed samples are not recommended for use in this assay." |
| At 2.5 mmol/L fructosamine: Negative interference > 83 mg/dL hemoglobin. (Indicates the need to avoid hemolyzed samples, suggesting this is a limitation rather than direct "acceptance" for hemolyzed samples) | ||
| Specificity (Ascorbic Acid) | Absence of significant interference at clinically relevant ascorbic acid levels. | At 2.5 mmol/L fructosamine: Negative interference > 4 mg/dL ascorbic acid. |
| At 4.2 mmol/L fructosamine: Negative interference > 8 mg/dL ascorbic acid. (Suggests interference at higher ascorbic acid levels, implying an implicit acceptance of lower levels/consideration for clinical context) | ||
| Specificity (Lipemic Interference) | Absence of significant interference at clinically relevant triglyceride levels. | At 2.5 mmol/L fructosamine: Positive interference > 242 mg/dL triglycerides. (Suggests interference at higher triglyceride levels, implying an implicit acceptance of lower levels/consideration for clinical context) |
| Reference Ranges | Should align with established clinical reference ranges for non-diabetic and diabetic populations. | For 55 non-diabetic subjects: 1.9 - 2.9 mmol/L (95th percentile 2.7 mmol/L). |
| For diabetic subjects: 2.1 - 5.0 mmol/L (10% of values below 2.7 mmol/L). (These are presented as external reference ranges, not directly "acceptance criteria" but used to frame the device's utility in a clinical context.) |
2. Sample Size and Data Provenance
- Test Set (Method Comparison): 49 sample pairs.
- Data Provenance: Not explicitly stated, but the comparison describes using a "commercially available calibrator as a reference" and "Serum samples were assayed in parallel," suggesting prospective collection for the purpose of this comparison study. The country of origin is not specified, but the submission is from the USA.
- Test Set (Reportable Range/Observed Range): 31 human serum samples.
- Data Provenance: "asymptomatic with respect to fructosamine," suggesting these were normal, healthy individuals. Again, likely prospective for this study, country of origin not specified.
- Test Set (Precision):
- Within Run: 20 data points for Level 1, 20 for Level 2.
- Total: 10 samples for Level 1, 10 for Level 2.
- Data Provenance: Not specified, but generally, precision studies use controls or pooled patient samples run repeatedly, likely prospective.
3. Number of Experts and Qualifications for Ground Truth for Test Set
- Not Applicable. This is an in vitro diagnostic assay directly measuring a biochemical marker (fructosamine). The "ground truth" for the method comparison is the measurement obtained from the predicate device (Sigma Diagnostics Fructosamine). For sensitivity, precision, and linearity, the ground truth is derived from the known concentrations in control materials or the inherent properties of the measurement system. Expert consensus is not used to establish the "ground truth" for the quantitative values of fructosamine.
4. Adjudication Method for the Test Set
- Not Applicable. As this is a quantitative chemical assay, expert adjudication in the traditional sense (e.g., for image interpretation) is not relevant. The "adjudication" is the direct comparison of quantitative results from the candidate device to the predicate device, or to known values from controls.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No. This type of study is typically relevant for medical imaging or subjective interpretation tasks where multiple human readers assess cases. This document describes an in vitro diagnostic assay, where the "reader" is an automated clinical chemistry analyzer (Hitachi 704). Therefore, an MRMC study is not applicable.
6. Standalone Performance (Algorithm Only)
- Yes, implicitly. The entire study describes the standalone performance of the "Thermo DMA Fructosamine Assay" reagent when run on an automated analyzer. There is no human interpretation or intervention in the measurement process itself beyond loading samples and calibrators. The results presented (Method Comparison, Precision, Sensitivity, Reportable Range, Specificity) are all measures of the algorithm/reagent's performance in isolation from subjective human interpretation.
7. Type of Ground Truth Used
- Comparator Device Measurements: For the method comparison study, the ground truth was essentially the quantitative results obtained from the predicate device (Sigma Diagnostics Fructosamine).
- Known Concentrations/Control Material: For precision, sensitivity, and linearity, the "ground truth" was established by using control materials with known or expected fructosamine concentrations or by the inherent capability of the instrument to resolve small changes in absorbance.
- Clinical Observation: For the "Reportable Range" study, 31 "asymptomatic" human serum samples were used to establish an observed normal range, implying a form of clinical ground truth for typical healthy levels.
8. Sample Size for the Training Set
- The document does not mention a separate "training set". This type of assay (a chemical reagent kit) does not involve machine learning or AI models that typically require a distinct training set. The "training" for the assay would be the development and optimization of the chemical reactions and parameters by Thermo DMA, which precedes the validation studies described here.
9. How Ground Truth for Training Set was Established
- Not Applicable. As there is no explicitly mentioned "training set" in the context of machine learning, the concept of establishing ground truth for it is not relevant to this submission. The development of the assay's methodology (e.g., optimal pH, incubation times, reagent concentrations) would have involved internal R&D, likely using chemically defined standards and characterized patient samples to ensure the reaction proceeds as intended and produces accurate results, but this is distinct from a "training set" for an AI algorithm.
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