(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 ( |
§ 864.5220 Automated differential cell counter.
(a)
Identification. An automated differential cell counter is a device used to identify one or more of the formed elements of the blood. The device may also have the capability to flag, count, or classify immature or abnormal hematopoietic cells of the blood, bone marrow, or other body fluids. These devices may combine an electronic particle counting method, optical method, or a flow cytometric method utilizing monoclonal CD (cluster designation) markers. The device includes accessory CD markers.(b)
Classification. Class II (special controls). The special control for this device is the FDA document entitled “Class II Special Controls Guidance Document: Premarket Notifications for Automated Differential Cell Counters for Immature or Abnormal Blood Cells; Final Guidance for Industry and FDA.”