(58 days)
HemosIL Silica Clotting Time is intended for the detection of Lupus Anticoagulants in human citrated plasma on the IL Coagulation Systems by the use of screening (SCT Screen) and confirmatory (SCT Confirm) reagents sensitized to phospholipid dependent antibodies. For in vitro diagnostic use.
HemosIL Silica Clotting Time is intended for the detection of Lupus Anticoagulants in human citrated plasma on the IL Coagulation Systems by the use of screening (SCT Screen) and confirmatory (SCT Confirm) reagents sensitized to phospholipid dependent antibodies.
Here's a summary of the acceptance criteria and study details for the HemosIL Silica Clotting Time device, based on the provided text:
Acceptance Criteria and Device Performance
| Acceptance Criteria Category | Specific Acceptance Criteria (Implied by Predicate Equivalence) | Reported Device Performance (HemosIL Silica Clotting Time) |
|---|---|---|
| Method Correlation | Substantially equivalent correlation to predicate devices (HemosIL LAC Screen and HemosIL LAC Confirm) | Slope: 1.099 |
| Intercept: -0.086 | ||
| r (correlation coefficient): 0.874 | ||
| Clinical Performance (Cut-off ≥ 1.20 for predicate) | Substantially equivalent diagnostic accuracy to predicate devices | Relative Sensitivity: 92.4% (95% C.I. = 82.1-97.0) |
| Relative Specificity: 100% (95% C.I. = 97.6-100.0) | ||
| Precision (Within Run) | Acceptable within-run variability | Normal Control: 2.47% CV |
| Low LA Control: 4.05% CV | ||
| High LA Control: 5.24% CV | ||
| Precision (Total) | Acceptable total variability | Normal Control: 2.95% CV |
| Low LA Control: 6.00% CV | ||
| High LA Control: 5.60% CV |
Note: The document explicitly states that the device "is substantially equivalent to the commercially available predicate devices (HemosIL LAC Screen and HemosIL LAC Confirm) in performance and intended use." This implies that the acceptance criteria were based on demonstrating comparable performance to these predicate devices rather than pre-defined absolute thresholds, for the correlation and clinical performance metrics. For precision, the reported %CVs fall within generally acceptable ranges for diagnostic assays.
Study Details
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Sample size used for the test set and the data provenance:
- Method Comparison Study: 210 citrated plasma samples (120 normals/90 abnormals)
- Clinical Study: 206 citrated plasma samples (121 normals/85 abnormals)
- Data Provenance: "in-house study" and "clinical study." The document does not specify the country of origin, but given the manufacturer (Lexington, MA, USA) and the 510(k) submission to the FDA, it is highly probable the studies were conducted within the US or followed US regulatory guidelines. The studies appear to be retrospective as they involved analyzing collected plasma samples.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The document does not explicitly state the number or qualifications of experts used to establish the ground truth for the test set. The ground truth appears to be based on the results from the predicate devices (HemosIL LAC Screen and HemosIL LAC Confirm) for comparison. The classification of samples as "normals" and "abnormals" for Lupus Anticoagulants would have been based on established clinical diagnostic criteria, likely involving expert interpretation of multiple tests, but this detail is not provided.
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Adjudication method for the test set:
- The document does not describe a specific adjudication method. As the primary comparison is against predicate devices, the "ground truth" for the test set is established by the results of those predicate devices.
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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. This device is an in-vitro diagnostic (IVD) assay, not an AI-assisted imaging or diagnostic tool that requires human reader interpretation. Therefore, an MRMC study is not applicable.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes. The reported performance metrics (slope, intercept, r, sensitivity, specificity, precision) are for the HemosIL Silica Clotting Time device running on an IL Coagulation System, indicating a standalone (algorithm/device only) performance evaluation. There is no mention of human-in-the-loop performance.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc):
- The ground truth for the test sets (both method comparison and clinical) appears to be established by the results obtained from the predicate devices (HemosIL LAC Screen and HemosIL LAC Confirm). Additionally, for the clinical study, it's mentioned that "All known Lupus Anticoagulant samples (n=48) tested as part of this study gave SCT normalized ratios > 1.24," suggesting that a subset of the abnormal samples had a pre-established clinical diagnosis of Lupus Anticoagulant, likely based on a combination of tests and expert consensus.
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The sample size for the training set:
- The document does not specify a separate "training set" in the context of machine learning. This is an IVD device, and the development process would involve formulation, optimization, and characterization rather than AI model training. The "in-house study" and "clinical study" are performance validation studies.
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How the ground truth for the training set was established:
- Not applicable as there is no mention of a separate training set in the context of an AI/ML model for this IVD device. The development of such a device focuses on reagent formulation and instrument calibration, typically using well-characterized samples and reference methods.
§ 864.7925 Partial thromboplastin time tests.
(a)
Identification. A partial thromboplastin time test is a device used for primary screening for coagulation abnormalities, for evaluation of the effect of therapy on procoagulant disorders, and as an assay for coagulation factor deficiencies of the intrinsic coagulation pathway.(b)
Classification. Class II (performance standards).