(120 days)
The ARCHITECT Homocysteine assay is a chemiluminescent microparticle immunoassay (CMIA) for the quantitative determination of total L-homocysteine in human serum or plasma on the ARCHITECT i System. Homocysteine values can assist in the diagnosis and treatment of patients suspected of having hyperhomocysteinemia and homocystinuria.
The ARCHITECT Homocysteine Calibrators are for the calibration of the ARCHITECT i System when used for the quantitative determination of total L-homocysteine in human serum or plasma.
The ARCHITECT Homocysteine Controls are for the estimation of test precision and the detection of systematic analytical deviations of the ARCHITECT i System (reagents, calibrators and instrument), when used for the quantitative determination of total L-homocysteine in human serum or plasma.
For in vitro diagnostic use.
The ARCHITECT Homocysteine assay is a one-step immunoassay for the quantitative determination of total L-homocysteine in human serum or plasma using CMIA technology, with flexible assay protocols, referred to as Chemiflex. Bound or dimerised homocysteine (oxidized form) is reduced by dithiothreitol (DTT) to free homocysteine, which is then converted to Sadenosyl homocysteine (SAH) by the action of the recombinant enzyme S-adenosyl homocysteine hydrolase (rSAHHase) in the presence of excess adenosine. The SAH then competes with acridinium-labeled S-adenosyl cysteine for particle-bound monoclonal antibody. Following a wash stage and magnetic separation, pre-trigger and trigger solutions are added to the reaction mixture and the resulting chemiluminescence is measured as relative light units (RLUs). An indirect relationship exists between the amount of homocysteine in the sample and the RLUs detected by the ARCHITECT i System optics.
The ARCHITECT Homocysteine assay is compared to the AxSYM Homocysteine assay. The acceptance criteria and the study results proving the device meets these criteria are as follows:
- Table of Acceptance Criteria and Reported Device Performance:
| Performance Metric | Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|---|
| Method Comparison (Regression) | Slope between 0.95 and 1.05 | 0.98 |
| Intercept close to 0 | -0.74 | |
| Correlation Coefficient (r) > 0.95 | 0.98 | |
| Precision | Substantially equivalent to predicate device | Substantially equivalent to predicate device |
| Linearity | Substantially equivalent to predicate device | Substantially equivalent to predicate device |
| Interferences | Substantially equivalent to predicate device | Substantially equivalent to predicate device |
Note: The acceptance criteria are implicit based on the statement of "substantially equivalent performance" and typical ranges for method comparison studies in clinical chemistry. The provided 510(k) summary does not explicitly state numerical acceptance criteria, but rather demonstrates equivalence to a predicate device.
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Sample size used for the test set and the data provenance:
- Sample Size: 456 plasma samples.
- Data Provenance: Not specified (country of origin, retrospective/prospective). Since it's a method comparison study for an in vitro diagnostic, it would typically involve clinical samples, likely prospective or a well-characterized retrospective cohort.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Not applicable. For an immunoassay, the "ground truth" is typically established by the reference method or comparative method, which in this case is the predicate device (AxSYM Homocysteine assay). The performance of the predicate device is assumed to be accurate.
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Adjudication method for the test set:
- Not applicable. This is a method comparison study for an in vitro diagnostic device, not an image-based diagnostic or clinical trial requiring expert adjudication of diagnoses. The predicate device's results serve as the comparison point.
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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:
- Not applicable. This is not an AI-based device for image interpretation or diagnosis by human readers. It is an in vitro diagnostic immunoassay.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, the study performed is a standalone performance assessment of the ARCHITECT Homocysteine assay against a predicate device. The assay itself is automated and does not involve a human in the loop for its direct analytical performance once a sample is loaded.
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The type of ground truth used:
- Comparative data with a legally marketed predicate device: The AxSYM Homocysteine assay results were used as the comparison "ground truth" to establish substantial equivalence.
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The sample size for the training set:
- Not applicable. This device is an immunoassay, not a machine learning or AI algorithm that requires a separate training set. Its chemical and mechanical principles are fixed during development.
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How the ground truth for the training set was established:
- Not applicable (see point 8).
§ 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.