(99 days)
Thrombonostika F1.2 is an enzymed-linked immunosorbent assay for the quantitative determination of prothrombin activation fragment 1.2 (F1.2) in human plasma. It is indicated as an aid to both assess the risk of thrombosis and monitor the efficacy of anticoagulant therapy.
Thrombonostika F1.2 is a two-stage enzymed-linked immunosorbent assay for the prothrombin activation peptide F.12. The high specificity of the solid-phase anti-F1.2 monoclonal antibody allows quantitation of nanomolar F1.2 in the presence of micromolar prothrombin that is typically found in plasma. Rabbit polyclonal antibodies to the calcium-dependent conformer of prothrombin (i.e., the amino terminal region present on both prothrombin and F1.2 ) coupled to horseradish peroxidase (HRP) serves as the conjugate with tetramethylbenzidine (TMB) used as the substrate.
In the first stage, test sample or calibrator is incubated with a monoclonal F1.2-specific antibody (murine) coated on a microelisa well. F1.2 binds to the solid-phase antibody. Following an incubation, unbound proteins (including prothrombin) are aspirated and the well washed with buffer. In the second stage, conjugate (rabbit) labeled with HRP is added. The enzyme-labeled antibody is bound to the solid-phase F1.2 complex. Following a wash and incubation with TMB substrate, blue color is produced that turns yellow hen the reaction is stopped with stop solution. Within limits, the amount of prothrombin fragment 1.2 is proportional to the color development.
Here is a summary of the acceptance criteria and study information for the Thrombonostika F1.2 device, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The provided document describes a modification to an existing device, Thrombonostika F1.2 (K911434). The study focuses on demonstrating substantial equivalence of the modified device to the original. Explicit, pre-defined quantitative "acceptance criteria" for each performance metric are not clearly stated in the document as separate, distinct criteria. Instead, the results themselves demonstrate that the modified device performs comparably to or within expected ranges of the original or ideal performance.
Therefore, the "acceptance criteria" are inferred from the demonstrated performance that leads to the conclusion of substantial equivalence.
| Performance Metric | Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|---|
| Equivalence to Original Device (Comparison Data without 0.25 nM calibrator vs. with 0.25 nM calibrator) | High correlation (R² approaching 1), slope near 1, intercept near 0, demonstrating agreement with original device values. | Without 0.25 nM calibrator: Coefficient of determination (R²) = 0.998. Estimated slope = 1.001. Estimated intercept = 0.001. 240 out of 268 test results (90%) fell in the 0.0-1.0 nM range. |
| Equivalence to Original Device (Comparison Data (fresh patient samples) current vs. modified version) | High correlation (R² approaching 1), slope near 1, intercept near 0, demonstrating agreement between current and modified versions. | Current vs. Modified Version: Coefficient of determination (R²) = 0.9999. Estimated slope = 0.987. Estimated intercept = 0.036. |
| Sensitivity | Minimum detectable F1.2 level, ideally low to detect small concentrations. | Minimum F1.2 level distinguishable from Calibrator A is 0.1 nM. |
| Accuracy | Mean recovery within an acceptable range (e.g., 80-120%), indicating accurate measurement across different concentrations. | Mean recovery of 113.5% (SD=13%) was obtained when purified F1.2 (0.5-20 nM) was added to 16 plasma samples from 5 donors. (The document does not explicitly state a pre-defined acceptance range for recovery, but 113.5% with SD 13% is presented as an acceptable outcome for accuracy). |
| Precision | Low intra-assay and total coefficients of variation (CV) and standard deviations (SD) for various F1.2 levels and kit lots, demonstrating reproducibility. | Estimates of total and intra-assay precision were calculated for each of three kit lots by assaying multiple replicates of Level I and Level II Controls on multiple plates and occasions. (Specific CV and SD values are not provided in the summary but are stated to have been calculated and considered in the conclusion of safety and effectiveness). |
2. Sample Size Used for the Test Set and Data Provenance
- Comparison Data (without 0.25 nM calibrator vs. with 0.25 nM calibrator): 268 test results. Data provenance is not explicitly stated (e.g., country of origin) but is implied to be from laboratory testing to compare versions of the device. The nature (retrospective/prospective) is not specified.
- Comparison Data (51 fresh patient samples): 51 fresh patient samples. Data provenance is implied to be from actual patient samples, likely retrospective or a small prospective collection for this specific comparison.
- Accuracy: 16 plasma samples from 5 different donors. Data provenance is laboratory-controlled, using added (spiked) purified F1.2.
- Precision: "Multiple replicates" of Level I and Level II Controls on "multiple plates and occasions" for "three kit lots." Specific numbers of replicates are not given in the summary, but it implies extensive internal testing. Provenance is laboratory testing.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
Not applicable. This is an in-vitro diagnostic (IVD) assay measuring a biomarker. The "ground truth" is established through the analytical measurement process itself using calibrators and controls, rather than expert interpretation of images or clinical cases.
4. Adjudication Method for the Test Set
Not applicable. As an IVD assay, adjudication by multiple experts is not relevant to establishing the ground truth for F1.2 concentration measurements. The assay itself provides a quantitative measurement.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
No, an MRMC comparative effectiveness study was not performed. This type of study is relevant for diagnostic imaging or interpretation tasks where human readers are involved. This device is an in-vitro diagnostic assay.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
Yes, the studies described are standalone performance evaluations of the assay itself. The Thrombonostika F1.2 is an ELISA kit, and its performance metrics (sensitivity, accuracy, precision, comparative analysis) measure the device's analytical capability independently. There is no human-in-the-loop component in the performance evaluation of the assay's output itself, although human operators perform the assay.
7. The Type of Ground Truth Used
The ground truth for this device's performance evaluation relies on:
- Quantifiable concentrations: Established by known values of calibrators and spiked samples with purified F1.2 (for accuracy).
- Reference measurements: Comparison to the performance of the original, legally marketed Thrombonostika F1.2 device (K911434) and analysis of fresh patient samples using both current and modified versions.
- Statistical analysis: Based on standard laboratory practices for determining analytical performance parameters like R², slope, intercept, sensitivity, and precision using replicates and controls.
8. The Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of an algorithm or statistical model. For an ELISA kit, the development and optimization process (analogous to "training") would involve extensive internal testing to establish reagent concentrations, incubation times, wash steps, etc. However, specific sample sizes for such development phases are not detailed in this 510(k) summary. The presented data represents the validation (test) phase.
9. How the Ground Truth for the Training Set was Established
As noted above, there isn't a "training set" in the sense of a dataset used to train an AI algorithm. For an IVD, the "ground truth" during development (training analog) would be established through:
- Known concentrations of F1.2: Using highly purified F1.2 and calibrated standards.
- Reference methods: Comparing experimental results to established, validated methods for F1.2 measurement or related coagulation markers during development.
- Clinical correlation: Indirectly, by ensuring the assay provides values that align with expected physiological states (e.g., elevated in thrombotic risk groups, depressed in anticoagulated patients), although this is more for clinical utility than analytical ground truth for individual measurements.
§ 864.7320 Fibrinogen/fibrin degradation products assay.
(a)
Identification. A fibrinogen/fibrin degradation products assay is a device used to detect and measure fibrinogen degradation products and fibrin degradation products (protein fragments produced by the enzymatic action of plasmin on fibrinogen and fibrin) as an aid in detecting the presence and degree of intravascular coagulation and fibrinolysis (the dissolution of the fibrin in a blood clot) and in monitoring therapy for disseminated intravascular coagulation (nonlocalized clotting in the blood vessels).(b)
Classification. Class II (performance standards).