(244 days)
For in vitro diagnostic use to identify and enumerate absolute counts of T lymphocyte (CD3+), helper/inducer T lymphocyte (CD3+CD4+) and suppressor/cytotoxic T lymphocyte (CD3+CD8+) subsets in blood.
- For use with any flow cytometer equipped with a 488 nm last and capable of detection in . the ranges: 515-545 nm, 562-607 nm, and >650 nm
- For use with erythrocyte lysed whole blood .
- For in vitro diagnostic use .
- To identify and enumerate absolute counts of CD3+ and CD3+CD4+ and CD3+CD8+ . lymphocytes
- To characterize and monitor some forms of immunodeficiency, such as in HIV infected . individuals
- To characterize and monitor some forms of autoimmune diseases .
The BDIS TriTEST CD4 fluorescein isothiocyanate (FITC)/CD8 phycoerythrin (PE)/CD3 peridinin chlorophyll protein (PerCP) reagent is a three-color, direct immunofluorescence reagent. When used with TRUCOUNT Absolute Count Tubes it is used for identifying and enumerating absolute counts of I lymphocytes (CD3+), helper/inducer T lymphocytes (CD3+CD4+) and suppressor/cytotoxic I lymphocytes (CD3+CD8+) in erythrocyte-lysed whole blood (LWB). The Becton Dickinson TnTEST / TRUCOUNT system for immunophenotyping consists of a flow cytometer (either from BDIS or from another manufacturer), conjugated monoclonal reagent (Tril EST CD4 FITC/CD8 PE/CD3 PeCP) and TRUCOUNT Absolute Count Tubes.
The process to obtain T lymphocyte subset absolute counts includes: 1) obtaining a whole blood sample, 2) adding a precise volume of whole blood directly to the Absolute Count Tube, 3) cell-surface antigen staining with three-color monoclonal antibody reagents, 4) erythrocyte lysis, and 5) flow cytometric acquisition and analysis of list mode data. Analysis for absolute counts requires that the bead 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 I x (beads/pellet)/(volume of blood sample).
Here's an analysis of the provided text, extracting the requested information about the acceptance criteria and the study that proves the device meets them:
Acceptance Criteria and Device Performance Study for BDIS TriTEST™ Reagent with TRUCOUNT Absolute Count Tubes
This submission does not explicitly state specific numerical acceptance criteria for performance metrics. Instead, it relies on demonstrating substantial equivalence to a predicate device (FACSCount cleared under K933486). The "acceptance criteria" are therefore inferred as achieving performance equivalent to or demonstrably safe and effective as the predicate device for the specified indications for use.
The study aims to establish this equivalence, particularly for identifying and enumerating absolute counts of T lymphocytes (CD3+), helper/inducer T lymphocytes (CD3+CD4+), and suppressor/cytotoxic T lymphocytes (CD3+CD8+).
1. Table of Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|---|
| Accuracy | Substantial equivalence to the predicate device (FACSCount) for CD3+, CD3+CD4+, and CD3+CD8+ absolute counts. | Accuracy data demonstrated the TriTEST/TRUCOUNT product's equivalence to FACSCount. "Results demonstrate that the products yield essentially equivalent performance characteristics." The TriTEST/TRUCOUNT system (for absolute counts) is substantially equivalent to the FACSCount system for CD3+, CD3+CD4+ and for CD3+CD8+. |
| Stability (Time-from-draw) | Blood specimens should be stained within a specified timeframe to maintain accurate absolute counts. | Blood specimens should be stained within 24 hours of draw. (Alternatively, stained within 48 hours of draw and analyzed within 6 hours). |
| Stability (Time-from-sample preparation) | Stained samples should be analyzed within a specified timeframe to maintain accurate absolute counts. | Analysis of stained samples should occur within 24 hours. (Alternatively, stained within 48 hours of draw and analyzed within 6 hours). |
| Within-specimen Reproducibility | Acceptable consistency in results when multiple aliquots from a single specimen are tested. | "Results demonstrated acceptable within-sample reproducibility." (Tested with 10 replicates from 1 high, 1 medium, and 1 low sample at BDIS, and 3 aliquots from each donor at 3 clinical sites). |
| Linearity | Linear response across a clinical range of lymphocyte and WBC concentrations. | "Results indicate a linear response over this range." (Determined using blood samples from 3 normal donors diluted to 5 concentrations, ranging from 16,700 to 200 lymphocytes/uL and from 31,000 to 2,500 WBC/uL). |
| Cross-reactivity | Monoclonal antibodies should maintain their specificity after conjugation and formulation. | "Conjugation and product formulation have not changed their specificity." (Cross-reactivity of clones is reported in literature). |
| Cross-platform Reproducibility | Acceptable comparability of results across different flow cytometer platforms. | Indicated 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.”