(73 days)
The ACTICLOT® dPT™ is intended for the qualitative determination of lupus anticoagulants (LA) in human plasma. This test is for in vitro diagnostic use.
ACTICLOT® dPT" is a test kit. It has three reagents that are used selectively for a screening protocol and a confirmatory protocol. LA Buffer" is used with dPT Activator" for the screening protocol. LA Phospholipids" is used with dPT Activator" for the confirmatory protocol. ACTICLOT® dPT" is a professional use qualitative test.
The provided document describes the ACTICLOT® dPT™ reagent kit, an in vitro diagnostic test for the qualitative determination of Lupus Anticoagulants (LA) in human plasma. The submission is a 510(k) summary, which aims to demonstrate substantial equivalence to a legally marketed predicate device (DVVtest® and DVVconfirm®). The study presented focuses on justifying this substantial equivalence rather than establishing novel acceptance criteria against a clinical gold standard.
Here's an analysis of the provided information:
1. Table of Acceptance Criteria (Implied) and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" in a quantitative sense as might be seen for a new device with clinical claims. Instead, it demonstrates "substantial equivalence" to a predicate device in terms of performance characteristics. The implied acceptance criterion for each category is "equivalent" to the predicate device.
| Performance Characteristic | Predicate Device Performance (DVVtest® and DVVconfirm®) | Subject Device Performance (ACTICLOT® dPT™) | Implied Acceptance Criteria for Substantial Equivalence |
|---|---|---|---|
| Precision (Intra-Assay CV) | See TABLE 3 for values (e.g., 0.3% - 3.2%) | See TABLE 2 for values (e.g., 0.5% - 3.8%) | Intra-assay CVs were within 3.8% (for subject device), similar to predicate. |
| Precision (Inter-Assay CV) | See TABLE 3 for values (e.g., 2.4% - 5.6%) | See TABLE 2 for values (e.g., 3.2% - 8.6%) | Inter-assay CVs were within 7.2% (for subject device), similar to predicate. |
| Accuracy / Method Comparison (Agreement) | Not directly stated as a single value, but inferred from the predicate's performance in accuracy matrices. | Study 1: 90.7% agreement with predicate. Study 2: 87.1% agreement with predicate. | Agreement of 87.1% to 90.7% with the predicate device. |
| Sensitivity (Detection of LA Positive Samples) | 18/23 (78.3%) LA positive samples identified. | 18/23 (78.3%) LA positive samples identified. | Identical percentage of LA positive samples identified as the predicate device. |
2. Sample Size Used for the Test Set and Data Provenance
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Precision Studies:
- Sample Size: The precision studies used control samples (LAtrol® Abnormal Control and LAtrol® Normal Control). The exact number of individual measurements or replicates for each control on each instrument is not explicitly stated, but it mentions "multiple tests performed over several days."
- Data Provenance: The studies were performed by American Diagnostica Inc. and "one field trial laboratory." This indicates a mix of in-house and external testing. The country of origin for the field lab is not specified. The studies appear to be prospective, specifically designed to gather precision data for the submission.
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Method Comparison (Accuracy) Studies:
- Sample Size:
- Study 1: 54 patient samples.
- Study 2: 93 patient samples.
- Data Provenance:
- Study 1: American Diagnostica, Inc. in Stamford, CT (USA).
- Study 2: Centre hospitalier universitaire de Sherbrooke, Fleurimont (Québec), Canada.
- The document describes testing "patient samples," which suggests these were clinical samples. It does not explicitly state if they were retrospective or prospectively collected for the study, but the context of "method comparison studies" implies they were collected and then tested with both devices.
- Sample Size:
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Sensitivity Studies:
- Sample Size: 23 prescreened LA positive samples.
- Data Provenance: Haemotology Department at University College London, UK. These were "prescreened LA positive samples," indicating they were likely retrospective samples with established LA status used for evaluating sensitivity.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
- Precision Studies: Ground truth was based on the assigned values of the control materials. No human experts were involved in establishing "ground truth" for the controls beyond the manufacturer's quality control processes.
- Method Comparison (Accuracy) Studies: The "ground truth" for these studies was the result obtained from the predicate device (DVVtest® and DVVconfirm®). No independent experts were used to establish a separate ground truth for LA status. The comparison was device-to-device.
- Sensitivity Studies: The samples were described as "prescreened LA positive samples." This implies that the LA positive status of these 23 samples was established prior to the study by standard clinical methods, potentially involving expert interpretation of multiple tests. However, the exact number of experts or their qualifications for this prescreening are not specified in the document.
4. Adjudication Method for the Test Set
- Precision, Accuracy, and Sensitivity Studies: The document does not describe any adjudication method (like 2+1 or 3+1 consensus) for the test results. The results appear to be direct outputs from the instruments. For the "prescreened LA positive samples" in the sensitivity study, the original method of establishing their "positive" status (which might have involved an adjudication process) is not detailed.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No MRMC comparative effectiveness study was done. This device is an in vitro diagnostic reagent kit that provides a quantitative measurement (clotting time) which is then interpreted qualitatively as LA positive or negative. It does not involve human readers interpreting images or complex data that would typically be associated with an MRMC study.
6. Standalone Performance (Algorithm Only Without Human-in-the-Loop Performance)
- Yes, the studies presented are all standalone. ACTICLOT® dPT™ is a reagent kit that provides a result (clotting time) on an automated coagulation analyzer. The "performance" described refers to the output of the instrument using the reagent. The test itself is described as a "professional use qualitative test," meaning a healthcare professional interprets the result. However, the studies evaluate the reagent's performance directly on the samples, without considering the variability introduced by different human interpretations of the final qualitative call, beyond what is inherent in reporting positive/negative for LA.
7. Type of Ground Truth Used
- Precision Studies: Manufacturer-assigned values for control materials.
- Method Comparison (Accuracy) Studies: The results obtained from the predicate device (DVVtest® and DVVconfirm®).
- Sensitivity Studies: "Prescreened LA positive samples," implying existing clinical diagnosis of LA based on other methods (which could involve expert consensus, pathology, or outcomes data, but this is not detailed). The document also mentions that no single LA test identifies all LA positive samples and recommends using a combination of two or more tests. This implies that the "true" LA positivity for the 23 samples was established by a combination of tests, rather than a single definitive ground truth.
8. Sample Size for the Training Set
- This submission is for a medical device (reagent kit). There is no "training set" in the context of machine learning. The device is not an AI/ML algorithm that learns from data.
9. How the Ground Truth for the Training Set was Established
- This question is not applicable as there is no "training set" for this type of device.
§ 864.7750 Prothrombin time test.
(a)
Identification. A prothrombin time test is a device used as a general screening procedure for the detection of possible clotting factor deficiencies in the extrinsic coagulation pathway, which involves the reaction between coagulation factors III and VII, and to monitor patients receiving coumarin therapy (the administration of one of the coumarin anticoagulants in the treatment of venous thrombosis or pulmonary embolism).(b)
Classification. Class II (performance standards).