(198 days)
The A/C Portable Enzymatic Homocysteine Assay on the A/C Diagnostics Reader (HyTek-205) is intended for the quantitative determination of total homocysteine (tHCY) in human plasma or serum. The device can assist in the diagnosis and treatment of patients suspected of having hyperhomocysteinemia. The A/C Enzymatic Homocysteine Assay is for in vitro diagnostic use.
The A/C Portable Enzymatic Homocysteine Assay is calibrated with A/C Enzymatic Homocysteine Assay Calibrators. A/C Enzymatic Homocysteine Assay Controls are assayed for the verification of the accuracy and precision of the A/C Portable Enzymatic Homocysteine Assay.
The A/C Enzymatic Homocysteine Assay measures tHCY. The principle of the assay is that after reduction, tHCY is depleted by Homocysteinase (rHCYase) and produces hydrogen sulfide (H2S), which is determined using N.N-dibutyl phenylene diamine (DBPDA), the combination of which forms a chromophore, the fluorescence is measured by the A/C Diagnostics Reader (HyTek-205).
The A/C Portable Enzymatic Homocysteine Assay is a three-steps reaction, which runs at room temperature. The total assay takes 80 minutes, and the A/C Diagnostics Reader is the only equipment needed.
Here's an analysis of the provided text regarding the A/C Portable Enzymatic Homocysteine Assay, focusing on acceptance criteria and the supporting study:
The provided document is a 510(k) summary for a medical device seeking substantial equivalence to a predicate device. It focuses on demonstrating that the new device performs as well as, or better than, the predicate. Therefore, the "acceptance criteria" are implicitly established by the performance of the predicate device. The study aims to show that the new device's performance aligns closely with that of the predicate.
Acceptance Criteria and Reported Device Performance
The acceptance criteria are not explicitly stated as numerical thresholds in this summary. Instead, they are implied by the reported performance of the predicate device, which the new device aims to match or closely approximate. The primary performance metric for comparison is the correlation and mean difference between the new device and the predicate.
| Acceptance Criteria (Implied by Predicate Performance) | Reported Device Performance (A/C Portable Enzymatic Homocysteine Assay) |
|---|---|
| Correlation with Predicate Device (A/C Automatic Enzymatic HCY Assay on Hitachi 912): High correlation expected, aiming for a regression line close to y=x and a correlation coefficient (R) close to 1. | Correlation and Regression: y = 1.01x + 0.91, with a correlation coefficient of R = 0.95. This indicates a strong positive linear relationship and close agreement with the predicate device. |
| Mean Difference from Predicate Device: A small mean difference, ideally close to 0, indicating minimal systematic bias between the two assays. Evaluation via Bland-Altman plot to ensure agreement across the assay range, with samples at both low and high concentrations agreeing well. | Mean Difference: The mean difference between the two assays was 1.05 umol/L. The document states that "The samples both at low and high concentrations of tHCY agreed well," suggesting acceptable agreement across the measuring range. |
| Within-Assay Coefficient of Variation (CV): Expected to be within a similar range as the predicate (3.0% to 4.8%). | Within-Assay CV: Ranged from 3.8% to 4.8%. This falls within the reported range of the predicate device (3.0% to 4.8%), indicating comparable precision. |
| Between-Assay Coefficient of Variation (CV): Expected to be within a similar range as the predicate (4.9% to 7.8%). | Between-Assay CV: Ranged from 5.0% to 7.4%. This also falls within the reported range of the predicate device (4.9% to 7.8%), indicating comparable precision. |
| Intended Use: The device must quantitatively determine total homocysteine (tHCY) in human plasma or serum and assist in the diagnosis and treatment of patients suspected of having hyperhomocysteinemia, for in vitro diagnostic use. This is a functional requirement, and the device's design and mechanism must support this. | Intended Use: The device description and "Indications for Use" section explicitly state: "The A/C Portable Enzymatic Homocysteine Assay on the A/C Diagnostics Reader (HyTek-205) is intended for the quantitative determination of total homocysteine (tHCY) in human plasma or serum. The device can assist in the diagnosis and treatment of patients suspected of having hyperhomocysteinemia. The A/C Enzymatic Homocysteine Assay is for in vitro diagnostic use." |
Study Details
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Sample Size used for the test set and the data provenance:
- Sample Size: 50 plasma samples.
- Data Provenance: Not explicitly stated regarding country of origin or specific demographics. The samples are referred to as "fifty plasma samples," implying they were clinical samples. The study is retrospective, as it compares the new device's results on these samples against those obtained from an existing, already cleared predicate device (the A/C Automatic Enzymatic HCY Assay on Hitachi 912).
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This is not applicable to this type of device and study. The "ground truth" for a quantitative assay like this is typically established by comparison to a reference method or a substantially equivalent predicate device, not by expert consensus on qualitative interpretation. The predicate device itself (A/C Automatic Enzymatic HCY Assay on Hitachi 912) served as the reference for comparison.
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Adjudication method for the test set:
- Not applicable. This is a quantitative assay comparison, not a diagnostic imaging or expert interpretation study requiring adjudication.
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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:
- No MRMC study was done. This is a comparison of two in vitro diagnostic devices, not an AI-assisted diagnostic tool involving human readers.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- This is partially applicable, as the "A/C Portable Enzymatic Homocysteine Assay on the A/C Diagnostics Reader" is a standalone system in the sense that it performs the measurement without human subjective interpretation of results, beyond the operator running the test. The study is comparing the performance of this standalone system against another standalone system (the predicate device). The performance metrics (correlation, regression, mean difference, precision) are all "algorithm only" or "device only" metrics.
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The type of ground truth used:
- The "ground truth" for this study was the results obtained from the predicate device, the A/C Automatic Enzymatic HCY Assay on Hitachi 912 (K030754). This is a common approach for demonstrating substantial equivalence for in vitro diagnostic devices.
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The sample size for the training set:
- The document does not explicitly mention a "training set" in the context of device development or machine learning. For in vitro diagnostic assays, performance characteristics are typically established through analytical studies (e.g., precision, linearity, interference) and clinical comparison studies (like this one) using patient samples, rather than a machine learning training paradigm.
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How the ground truth for the training set was established:
- Not applicable, as a "training set" in the machine learning sense is not described. The predicate device's performance was already established through its prior 510(k) clearance (K030754).
§ 862.1377 Urinary homocystine (nonquantitative) test system.
(a)
Identification. A urinary homocystine (nonquantitative) test system is a device intended to identify homocystine (an analogue of the amino acid cystine) in urine. The identification of urinary homocystine is used in the diagnosis and treatment of homocystinuria (homosystine in urine), a heritable metabolic disorder which may cause mental retardation.(b)
Classification. Class II.