(165 days)
The Homocysteine Enzymatic Assay is an in vitro test for the quantitative determination of total L-homocysteine in human serum and plasma on Roche/Hitachi cobas c systems. The assay can assist in the diagnosis of patients suspected of having hyperhomocysteinemia or homocystinuria.
The Homocysteine Calibrator Kit is intended for use in the calibration of quantitative Roche methods on Roche clinical chemistry analyzers as specified in the value sheets.
The Homocysteine Control Kit is intended for use in quality control by monitoring accuracy and precision for the quantitative methods as specified in the value sheets.
Assay: The Homocysteine Enzymatic Assay is based on an enzyme cycling assay principle that assesses the co-substrate conversion product. In this assay, oxidized homocysteine (Hcy) is first reduced to free Hcy which then reacts with a co-substrate, S-adenosylmethionine, to form methionine and S-adenosylhomocysteine (SAH), catalyzed by a Hcy S-methyltransferase. SAH is assessed by coupled enzyme reactions where SAH is hydrolyzed into adenosine (Ado) and Hcy by SAH hydrolase, and Hcy is cycled into the Hcy conversion reaction to form a reaction cycle that amplifies the detection signal. The formed Ado is immediately hydrolyzed into inosine and ammonia which reacts with glutamate dehydrogenase with concomitant conversions of NADH to NAD*. The concentration of Hcy in the sample is indirectly proportional to the amount of NADH converted to NAD which is measured spectrophotometrically at 340 nm.
Calibrator: The Homocysteine Calibrator Kit is a liquid, ready-for-use calibrator based on human serum. It is a single level calibrator with lot specific values and diluted on board the analyzer to create a 5-point calibration curve.
Control: The Homocysteine Control Kit consists of two ready-for-use controls based on human serum. The adjusted concentrations of the control components are in the low range for Control 1 and in the elevated range for Control 2.
This response summarizes the provided 510(k) Summary for the Homocysteine Enzymatic Assay, Calibrator Kit, and Control Kit. The document primarily focuses on demonstrating substantial equivalence to predicate devices rather than detailing a specific study to prove the device meets acceptance criteria. Therefore, some requested information, particularly regarding ground truth establishment, expert qualifications, adjudication methods, and MRMC studies, is not present in the provided text.
Here's the breakdown of the available information:
1. Table of Acceptance Criteria and Reported Device Performance
The 510(k) Summary presents a comparison of the draft device's features, including performance characteristics, against a predicate device. This comparison implicitly serves as a form of acceptance criteria, where the new device's performance is deemed acceptable if it is substantially equivalent to the cleared predicate.
| Feature / Acceptance Criteria (Implicit from Predicate) | Reported Device Performance (Draft Device) |
|---|---|
| Intended Use | In vitro test for quantitative determination of L-homocysteine in human serum and plasma on Roche/Hitachi cobas c systems. Assists in diagnosis of hyperhomocysteinemia or homocystinuria. |
| Sample Types | Serum, Lithium Heparin, K2EDTA, and K3EDTA |
| Instrument Platform | cobas c 501 |
| Calibrator | Homocysteine Calibrator; single level, diluted to form a 5-point calibration |
| Calibration Frequency | Every 7 days, after reagent lot change, and as required following quality control procedures |
| Calibration Mode | RCM |
| Controls | Homocysteine Controls |
| Reagent Active Ingredients | R1: S-adenosylmethionine, TCEP, 2-oxoglutarate, NADH; R2: homocysteine S-methyltransferase, glutamate dehydrogenase, casein (bovine); R3: adenosine deaminase (bovine), S-adenosyl-homocysteine hydrolase, casein (bovine) |
| Reagent Stability (Unopened) | 2-8 °C until expiration date |
| Reagent Stability (On-board in use) | 4 weeks |
| Measuring Range | 3 – 50 µmol/L |
| Lower Limits of Measure | LoB = 3 µmol/L; LoD = 3 µmol/L |
| Precision (CV) | Hcy Control 1: Mean 12.2 µmol/L, CV Repeatability 1.5%, CV Intermediate Precision 2.1% |
| Hcy Control 2: Mean 39.1 µmol/L, CV Repeatability 1.8%, CV Intermediate Precision 2.0% | |
| Human serum 1: Mean 8.26 µmol/L, CV Repeatability 2.0%, CV Intermediate Precision 2.3% | |
| Human serum 2: Mean 13.1 µmol/L, CV Repeatability 1.8%, CV Intermediate Precision 2.1% | |
| Human serum 3: Mean 30.0 µmol/L, CV Repeatability 1.4%, CV Intermediate Precision 1.8% | |
| Human serum 4: Mean 44.4 µmol/L, CV Repeatability 2.0%, CV Intermediate Precision 2.2% | |
| Expected Values | US: 15 µmol/L cut-off for normal in adults. Europe: 12 µmol/L cut-off for normal in adults. |
| Interferences | Methotrexate, carbamazepine, phenytoin, nitrous oxide, anticonvulsants, or 6-azuridine triacetate may cause higher Hcy levels. S-Adenosylhomocysteine (SAH) causes positive interference but is at sub-nmol/L in normal plasma. No significant interference from Icterus, Hemolysis (up to H index 100), Lipemia (up to L index 250), Triglycerides (up to 1790 mg/dl). No interference from common drug panels, Glutathione (0.5 mmol/L), Cystathionine (100 µmol/L), and Pyruvate (0.5 mmol/L). 3-deazaadenosine inhibits key enzymes. Gammopathy (IgM) may cause unreliable results. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state the sample size for a "test set" in the context of a clinical validation study. The precision data provided refers to "Hcy Control 1," "Hcy Control 2," and "Human serum 1, 2, 3, 4." The number of samples for each of these categories is not specified.
The data provenance (country of origin, retrospective/prospective) is not mentioned in the provided text.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This information is not available in the provided 510(k) summary. The document focuses on analytical performance characteristics rather than clinical diagnostic accuracy requiring ground truth established by experts.
4. Adjudication Method for the Test Set
This information is not provided.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done
An MRMC study is typically associated with imaging devices or diagnostic tests where human interpretation is a critical component. This device is an in vitro diagnostic (IVD) assay for quantitative determination of a biomarker. Therefore, an MRMC comparative effectiveness study involving human readers would not be applicable or expected for this type of device, and no such study is mentioned.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done
The provided data pertains to the analytical performance of the automated Homocysteine Enzymatic Assay on Roche/Hitachi cobas c systems. This inherently represents standalone (algorithm only/instrument only) performance, as it measures the assay's ability to precisely and accurately quantify Homocysteine in biological samples. The reported precision and interference studies demonstrate this standalone performance.
7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)
For the analytical performance studies (e.g., precision, measuring range, interference), the "ground truth" is established by:
- Known concentrations: For controls and calibrators, the concentrations are precisely manufactured and known.
- Reference methods or accepted analytical techniques: For validation of accuracy and linearity, comparison to established reference methods or highly accurate laboratory methods would typically be employed, although specific details are not provided in this summary.
- Spiked samples: Interference studies often involve spiking samples with known interferents to assess their effect.
There is no mention of expert consensus, pathology, or outcomes data as a ground truth for the performance claims presented in this analytical device summary.
8. The Sample Size for the Training Set
This information is not available in the provided 510(k) summary. The document describes an enzymatic assay, not an AI or machine learning algorithm that typically requires a distinct training set. The "training" in this context would likely refer to method development and optimization, for which specific sample sizes might not be explicitly documented in a 510(k) summary focused on substantial equivalence.
9. How the Ground Truth for the Training Set Was Established
As noted above, this information is not available as the context for a "training set" in an AI/ML sense is not relevant here. For the development and optimization of the enzymatic assay, the "ground truth" would be established through a combination of chemical principles, known substrate/product concentrations, and potentially comparison with established methods during the R&D phase.
§ 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.