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510(k) Data Aggregation
(338 days)
For in vitro diagnostic use to identify and enumerate percentages and absolute counts of CD3+ and CD3+CD4+ lymphocytes in blood.
For use with any flow cytometer equipped with a 488 nm laser and capable of detection in the ranges: 515-545 nm, 562-607 nm, and > 650 nm.
For use with erythrocyte-lysed peripheral whole blood.
For use with or without an isotype control.
To characterize and monitor some forms of autoimmune disease.
To characterize and monitor some forms of immunodeficiency disease, such as in HIV-infected individuals.
The BDIS TriTEST CD3 fluorescein isothiocyanate (FITC)/CD4 phycoerythrin (PE)/CD45 peridinin chlorophyll protein (PeCP) reagent is a three-color, direct immunofluorescence reagent for identifying and enumerating percentages of T lymphocytes (CD3+) and T-helper (CD3+CD4+) cells in erythrocyte-lysed whole blood (LWB). When used with TRUCOUNT Absolute Count Tubes, the product will yield absolute counts in cells/UL. The Becton Dickinson TriTEST/TRUCOUNT system for immunophenotyping consists of a flow cytometer (either from BDIS or from another manufacture), conjugated monoclonal reagent (TriTEST CD3 FITC/CD4 PE/CD45 PerCP) and TRUCOUNT Absolute Count Tubes.
The process to obtain lymphocyte subset percentages includes: 1) obtaining a whole blood sample, 2) cell-surface antigen staining with three-color monoclonal antibody reagents, 3) erythrocyte lysis, and 4) flow cytometric acquisition and analysis of list mode data. Analysis involves computing the ratio of reagent-positive events (CD3+CD4+) to the CD45 positive events, and expressing the ratio as a percentage.
To obtain absolute counts, the TriTEST reagent and whole blood are added directly to an Absolute Count Tube prior to lysis. The remaining process, until analysis, is identical to that for percentages. Analysis for absolute counts requires that an additional region, be identified and the events in this region counted. The proportion of reagent positive events to bead events (P) is computed. The absolute count is P x (beads/pellet)/(volume of blood sample).
When monoclonal antibody reagents are added to human whole blood, the fluorochrome-labeled antibodies bind specifically to antigens on the surface of leukocytes, thus identifying lymphocyte populations. The patient blood sample is added to the counting bead pellet and is treated with fluorochrome-labeled antibodies and the erythrocytes are lysed with FACS Lysing Solution. The flow cytometer is set up so that cell populations for most samples occupy approximately the same region of fluorescence space. The sample is then introduced into the flow cytometer and the stained cells and beads fluoresce when excited by a laser beam.
The three-color reagent permits identification of lymphocyte subsets using fluorescence gating instead of forward scatter gating. This three-color reagent allows direct gating on the CD45-positive population using a combination of fluorescence and side scatter parameters. By gating on the CD45-positive population, a maximum number of lymphocytes may be captured in the gate and non-lymphocyte contamination may be minimized.
Here's an analysis of the provided text, focusing on the acceptance criteria and the study that proves the device meets those criteria:
Device Name: Becton Dickinson TriTEST24 reagent CD3 FITC/CD4 PE/CD45 PerCP; TRUCOUNTTM Absolute Count Tubes
Intended Use: For in vitro diagnostic use to identify and enumerate percentages and absolute counts of CD3+ and CD3+CD4+ lymphocytes in blood.
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state numerical acceptance criteria in a clear, quantitative manner. Instead, performance is generally described in terms of "equivalence," "acceptable," and "good correlation" compared to a predicate device or expected behavior.
| Performance Characteristic | Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|---|
| Accuracy (Absolute Counts CD3+) | Substantial equivalence to predicate device (FACSCount system) | "Accuracy data demonstrated the TriTEST/TRUCOUNT product's equivalence to FACSCount." |
| Accuracy (Absolute Counts CD3+CD4+) | Substantial equivalence to predicate device (FACSCount system) | "Accuracy data demonstrated the TriTEST/TRUCOUNT product's equivalence to FACSCount." |
| Use with or without Isotype Control | Performance should be acceptable and comparable in both scenarios | "Data indicated that the reagent may be used with or without an isotype control." |
| Reference Range Studies | Ability to establish site-specific reference ranges | "The reference range for CD3+ and CD3+CD4+ lymphocytes was a function of sex and site... Each site must determine its own reference range." (Implies the device provides robust data for this purpose). |
| Stability (Age of blood pre-staining) | Acceptable performance over a defined time period post-draw | "Staining the samples within 24 hours of draw and analyzing samples within 24 hours of staining or alternatively, staining the samples within 48 hours of draw and analyzing them within 6 hours is recommended." (Implies stability within these parameters). |
| Stability (Age of stain post-staining) | Acceptable performance over a defined time period post-staining | "Staining the samples within 24 hours of draw and analyzing samples within 24 hours of staining or alternatively, staining the samples within 48 hours of draw and analyzing them within 6 hours is recommended." (Implies stability within these parameters). |
| Within-specimen Reproducibility | Acceptable consistency within replicates from the same specimen | "Results demonstrated acceptable within-sample reproducibility." |
| Linearity | Proportional response over a relevant concentration range | "Results indicate a linear response over this range [16,700 to 200 lymphocytes/UL and from 31,000 to 2,500 WBC/UL]." |
| Cross Reactivity / Specificity | Maintenance of established specificity | "Conjugation and product formulation have not changed their specificity [as reported in literature]." |
| Cross-Platform Reproducibility (Percentages) | Acceptable performance on non-BD devices | "For percentage results, the reagent may be used with flow cytometers not made by Becton Dickinson." |
| Cross-Platform Reproducibility (Absolute Counts) | Good correlation with BD devices, with transparency about potential bias | "There was a small (<20%) non-zero bias, but good correlation between results on a Becton Dickinson flow cytometer versus a Coulter cytometer was observed. Therefore, users will be advised that they must validate performance characteristics for absolute counts." (Implicit acceptance despite bias, with user guidance). |
2. Sample Sizes Used for the Test Set and Data Provenance
- Accuracy Study (Absolute Counts CD3+): 197 donors (152 abnormal, 45 normal).
- Accuracy Study (Absolute Counts CD3+CD4+): Number of donors not explicitly stated, but "data for CD3+CD4+ was grouped according to range of number of cells."
- Within-specimen reproducibility (BDIS lab): 1 high, 1 medium, and 1 low specimen (10 replicates each).
- Within-specimen reproducibility (Clinical sites): n=94 for CD3+ donors, n=80 for CD3+CD4+ donors (3 aliquots from each donor).
- Linearity: Blood samples from 3 normal donors.
- Stability: Whole blood samples were tested at 0, 24, 48, and 72 hours post-draw, and stained samples at 0 and 24 hours from staining. (Number of donors not specified).
- Reference Range: Not specified, but suggests multiple sites.
Data Provenance:
The studies were performed at:
- Cleveland Clinic
- Johns Hopkins Hospital
- Institute of Tropical Medicine
- University of North Carolina
- Becton Dickinson Immunocytometry Systems laboratories in San Jose, California
Indicates a multi-center study involving both a commercial lab and academic/clinical institutions within the USA (Cleveland Clinic, Johns Hopkins, UNC). "Institute of Tropical Medicine" might suggest international data, but the context generally points to the US for the other named sites. The data appears to be prospective or a mix of retrospective and prospective, generated specifically for these performance studies.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not provide this information. The predicate device comparison implies the "ground truth" for accuracy was the performance of the BDIS FACSCount system, which is another device rather than expert consensus on patient samples. For other analyses like reproducibility or linearity, the "ground truth" is inherent to the measurements and expected biological/analytical behavior rather than expert interpretation of a diagnostic outcome.
4. Adjudication Method for the Test Set
Not applicable. The "ground truth" is derived from direct measurements and comparison to a predicate device, not through expert review needing adjudication of subjective interpretations.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not performed. The device is for objective enumeration of cell populations, not for image interpretation or diagnosis that would typically involve multiple human readers. The comparison is between the new device and a predicate device (FACSCount system) for quantitative measurements.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, the studies evaluate the standalone performance of the TriTEST/TRUCOUNT system. While human operators are involved in sample preparation and operating the flow cytometer, the evaluation focuses on the accuracy, reproducibility, and linearity of the device's measurements of cell populations, independent of human diagnostic interpretation. The flow cytometer, reagents, and counting tubes constitute the "algorithm" or system being tested.
7. The Type of Ground Truth Used
The primary ground truth for accuracy was the performance of the predicate device, the BDIS FACSCount system.
For other studies:
- Reproducibility: The consistency of repeated measurements on the same sample.
- Linearity: The expected proportional response to serial dilutions, likely confirmed instrumentally or against established cell count methodologies.
- Stability: Measured values over time compared to baseline.
8. The Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of machine learning or algorithm development. The studies described are validation studies of an established methodology (flow cytometry with specific reagents and beads) against a predicate device. Therefore, a separate, distinct "training set" as understood in AI/ML is not applicable here. The development of the formulation of the reagent itself would have preceded these validation studies.
9. How the Ground Truth for the Training Set Was Established
As noted above, a "training set" in the context of an AI/ML algorithm is not described. The device is a diagnostic assay kit (reagents and counting tubes) used with a flow cytometer. The "ground truth" for development of such a kit would trace back to established immunological principles and cell biology, validated through prior scientific research and predicate device performance.
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