(51 days)
Intended for in vitro diagnostic use in the quantitative determination of total homocysteine (HCY) in serum or EDTA plasma using the ACS:180 System. This diagnostic test is designed to quantitatively measure HCY in serum or EDTA plasma. Such measurement can aid in the diagnosis and treatment of patients suspected of having homocystinuria or hyperhomocysteinemia.
The ACS:180 HCY assay is a competitive immunoassay using direct, chemiluminescent technology. It is intended to measure the amino acid Homocysteine (HCY) in serum or EDTA plasma. The homocysteine assay requires four separate reagents, which are added sequentially. A Reducing Reagent releases protein bound and dimerized HCY in a sample or control to free HCY. A Enzyme Reagent uses the enzyme S-adenosylhomocysteine hydrolase to convert the free HCY to S-adenosylhomocysteine (SAH). SAH from a calibrator, control, or sample competes with SAH bound to the Solid Phase for binding to a monoclonal anti SAH antibody-acridinium ester conjugate in the Lite Reagent. Following incubation. unbound SAH and anti SAH-acridinium ester conjugate are washed from the Solid Phase. The chemiluminescence of the acridinium ester bound to the Solid Phase is measured. The amount of chemiluminescence is inversely proportional to the amount of HCY that was present in the sample.
This document describes the Bayer Diagnostics ACS:180 HCY Assay, a device for measuring Homocysteine (HCY) levels.
Here's an analysis of the provided information regarding acceptance criteria and the study that proves the device meets them:
1. A table of acceptance criteria and the reported device performance
The provided document doesn't explicitly state numerical "acceptance criteria" for the ACS:180 HCY assay in the traditional sense (e.g., a minimum sensitivity or specificity). Instead, the performance is demonstrated by comparing it to a legally marketed predicate device. The primary performance metric presented is the correlation with the predicate device.
| Acceptance Criterion | Reported Device Performance (ACS:180 HCY Assay) |
|---|---|
| Equivalence to Predicate Device (Abbott IMx Homocysteine assay) | Linear regression: IMx = 0.98 (ACS:180) + 0.43 µmol/L |
| Correlation with Predicate Device | R = 0.981 |
2. Sample sized used for the test set and the data provenance
- Sample Size: 106 samples
- Data Provenance: The document does not specify the country of origin of the data or whether the samples were collected retrospectively or prospectively.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
This information is not provided in the document. For an immunoassay device like this, the "ground truth" is typically established by the results from a reference method or a predicate device. Expert adjudication is not usually applied to the readings of quantitative assays in the same way it would be for image-based diagnostic AI.
4. Adjudication method for the test set
This information is not applicable and therefore not provided. Adjudication methods (like 2+1, 3+1) are typically used in scenarios where human interpretation of complex data (e.g., medical images) is involved to establish a ground truth or resolve discrepancies. For a quantitative immunoassay, the values produced by the reference method (in this case, the predicate device) are taken as the comparative standard.
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 information is not provided and is not applicable to this type of device. The ACS:180 HCY Assay is an automated in vitro diagnostic test, not an AI-assisted diagnostic tool that requires human interpretation in the loop. Therefore, an MRMC study comparing human readers with and without AI assistance would not be relevant.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, the study presented demonstrates the standalone performance of the ACS:180 HCY assay. The device directly measures HCY levels in serum or EDTA plasma without human interpretation influencing the measurement outcome. Its performance is compared directly against the predicate device's measurements.
7. The type of ground truth used
The "ground truth" for evaluating the performance of the ACS:180 HCY Assay was established by comparison to the Abbott IMx Homocysteine assay, which is a legally marketed predicate device. While not "pathology" or "outcomes data" in the strictest sense, the predicate device serves as the accepted standard for measuring HCY levels against which the new device's accuracy and correlation are assessed.
8. The sample size for the training set
This information is not provided. For a traditional immunoassay, there isn't a "training set" in the machine learning sense. Assay development involves optimizing reagents, protocols, and calibration curves, but it's not typically described as a training set.
9. How the ground truth for the training set was established
This information is not provided and is not applicable for the reasons mentioned in 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.