(75 days)
For In Vitro Diagnostic Use Mouse Anti-Human T-cell, CD3/FITC, UCHT1 + - Mouse Anti-Human T-cell, CD4/RPE, MT310 (DAKO Anti-CD3/FITC and Anti-CD4/RPE) has been developed for use in flow cytometry for the analysis of CD3 and CD4* T-cells. This reagent allows simultaneous detection and quantification of CD3CD4 cells (CD4 positive T-lymphocytes) in normal and pathological conditions such as immunodeficiency disorders. It is one component of the suggested monoclonal antibody (MAb) combinations for routine immunophenotyping of lymphocytes in peripheral blood using flow cytometry.
Purified mouse anti-human CD3, Clone UCHT1, conjugated with fluorescein isothiocyanate, isomer 1 (FITC) + purified mouse anti-human CD4, Clone MT310, conjugated with R-phycoerythrin, present in 0.05M Tris-HCl buffer, pH 7.2, 15 mM NaNo, 0.1M NaCl, stabilized with 1% carrier protein Subpopulations of lymphocytes may be stained with fluorochrome-conjugated antibody and evaluated in peripheral blood specimens when contaminating red blood cells (RBC's) are lysed prior to flow cytometric analysis. A subpopulation of WBC's are selected for assessment based upon cell morphology.
Here's an analysis of the provided text, focusing on the acceptance criteria and the study details:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criterion | Reported Device Performance |
|---|---|
| CD3+ T-cells: Correlation with predicate DAKO CD3/FITC | Correlation greater than 0.96 (using whole blood method for flow cytometry) |
| CD4+ T-cells: Correlation with predicate DAKO CD4/RPE | Correlation greater than 0.96 (using whole blood method for flow cytometry) |
| Linearity (CD3/FITC, UCHT1): | y = 0.02 + 0.98x; r = 0.999 |
| Linearity (CD4/RPE, MT310): | y = - 0.01 + 1.03x; r = 0.999 |
| Reproducibility: | Measured at three concentrations of each antigen using replicates from peripheral blood on two different flow cytometers. (No specific quantitative metric given, but implied successful.) |
| Cross-reactivity: | Measured with peripheral blood cells (red blood cells, monocytes, granulocytes, lymphocytes, and platelets). (No specific quantitative metric given, but implied successful.) |
Note: The document states that the correlation "approached a direct 1:1 comparison," which is a qualitative description supporting the quantitative correlation of >0.96. The document doesn't explicitly list "acceptance criteria" but rather presents "technological performance characteristics" that were evaluated. The table above frames these evaluations as implicit acceptance criteria based on the demonstrated performance.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document mentions "peripheral blood samples obtained from apparently healthy adults." It does not specify an exact number of samples or subjects.
- Data Provenance: The data appears to be prospective as it describes the completion of "flow cytometric tests of peripheral blood samples." The country of origin is not explicitly stated.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- The concept of "experts" establishing ground truth in the traditional sense (e.g., radiologists interpreting images) is not directly applicable here.
- The ground truth in this context is established by the predicate devices (DAKO CD3/FITC and DAKO CD4/RPE), which are previously FDA-cleared monoclconal antibodies for measuring CD3 and CD4+ T-cells using flow cytometry.
- The initial validation of the antibody clones (UCHT1 for CD3 and MT310 for CD4) was done at international workshops: the First Leukocyte Typing Workshop (Paris, 1982) and the Second Leukocyte Typing Workshop (Boston, 1984), respectively. These workshops involved numerous scientific experts in immunology and cell typing, whose collective findings established the specificity and identity of these markers.
4. Adjudication Method for the Test Set
- No explicit adjudication method (like 2+1 or 3+1) is mentioned, nor is it typically relevant for this type of in vitro diagnostic device. The comparison is against established predicate devices, which serve as the reference.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, an MRMC comparative effectiveness study was not done. This type of study typically involves multiple human readers evaluating cases with and without AI assistance to measure improvements in diagnostic performance. The device described is a flow cytometry reagent, not an AI-powered diagnostic imaging tool.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study
- Yes, the study is essentially "standalone" in principle, but the concept of "algorithm" is different. The device itself (the reagent) is evaluated for its direct performance in detecting and enumerating cell populations using flow cytometry. While a human operates the flow cytometer and interprets the data, the performance being tested is that of the reagent itself in yielding accurate counts when compared to a reference standard (predicate devices). There is no "AI algorithm" involved in the sense of a software interpreting images or other complex data autonomously.
7. Type of Ground Truth Used
- The ground truth is established by the performance of predicate devices (DAKO CD3/FITC and DAKO CD4/RPE), which are themselves previously cleared and validated reagents for the accurate measurement of CD3 and CD4+ T-cells.
- Further foundational ground truth for the antibody clones was established through expert consensus (clustering at leukocyte typing workshops) regarding their specificity for the target antigens.
8. Sample Size for the Training Set
- The document does not report a separate "training set" in the context of an algorithm or machine learning model. This is an immunoassay reagent, not an AI device. The development of the reagent involves laboratory work, but not "training data" in the AI sense.
9. How the Ground Truth for the Training Set Was Established
- Since there's no "training set" for an algorithm in this context, this question is not applicable. The development of the individual antibody clones (UCHT1 and MT310) involved extensive biological research and validation, including the clustering at leukocyte typing workshops, to establish their specificity and utility.
§ 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.”