(177 days)
Thermo Scientific Cyto-Cal™ Count Tubes are used for determining absolute counts of leucocytes in blood.
Thermo Scientific Cyto-Cal™ Count Tubes are used with the immunophenotyping reagents BD TriTEST™, flow cytometers BD FACS Calibur or BD FACS Canto, and software BD CellQuest or DIVA. Thermo Scientific Cyto-Cal™ Count Tubes can be used with the BD FACS™ Loader. This in vitro diagnostic device is intended for clinical use only.
Thermo Scientific Cyto-Cal™ Count Tubes contain uniform 5.4 µm microspheres encapsulated with three dyes. The single tube contains fluorescent beads that have equivalent emissions to multiple channels for FITC. PE. Per-CP. PE-Cy5, APC. Each tube contains known number of fluorescent particles as indicated on the product label.
The provided text describes the 510(k) summary for the Thermo Scientific Cyto-Cal™ Count Tubes. Here's a breakdown of the acceptance criteria and the study that proves the device meets them:
1. A table of acceptance criteria and the reported device performance
The document doesn't explicitly list "acceptance criteria" in a separate table with pass/fail remarks. However, it presents the results of several performance studies that imply the acceptance criteria were met based on the conclusion of substantial equivalence to the predicate device.
| Study Type | Implied Acceptance Criteria (Based on Predicate Equivalence) | Reported Device Performance (Thermo Scientific Cyto-Cal™ Count Tubes) |
|---|---|---|
| Precision | Comparable CVs to predicate device for low, medium, and high cell levels. | Intra-assay precision: |
- CD3+ cells: CVs ranged from 4.9% (3602 cells/µL) to 6.2% (549 cells/µL).
- CD4+ cells: CVs ranged from 4.7% (1996 cells/µL) to 6.9% (369 cells/µL). |
| Dilution Recovery | Recovery within +/- X% of expected value. | Recovery was within +/- 10% of expected value for levels tested: - 0 to 1693 cells/µL for CD3+CD4+ cells.
- 0 to 3923 cells/µL for CD3+ cells. |
| Method Comparison | Strong correlation (R value > 0.99) with the predicate device. | Correlation Coefficient (R value) to predicate BD Trucount Tubes: - CD3+: > 0.99 (range 1 cell/µL to 2463 cells/µL).
- CD4+: > 0.99 (range 0 cells/µL to 1947 cells/µL).
External Evaluation: Correlation coefficients (r-value) met acceptance criteria for CD3+, CD4+, CD8+, CD16+CD56+, CD19+, and CD4/CD8 ratio. |
| Carryover Study | Carry-over less than X%. | Carry-over from high cell count sample to low cell count sample is less than 5%. |
| Sample Stability | Cells count within +/- X% of first test for specified times and temperatures. | Cells count are within +/- 10% of first test for up to 72 hours at 2 to 8 °C for blood samples, and for up to 12 hours at 2 to 8 °C for antibody-labeled and lysed blood samples. |
| Reagent Shelf-Life Stabilities | Stable for X months at specified temperature. | Real-time stability studies demonstrate the reagent is stable for at least 16 months at room temperature. Stability studies will continue for 24 months. |
2. Sample size used for the test set and the data provenance
- Precision:
- Sample Size: Three samples (representing low, medium, and high cell levels of CD3+ and CD4+) were used. Each sample was run 21 times.
- Data Provenance: Not specified, but generally, these are laboratory-controlled samples for repeatability.
- Dilution Recovery:
- Sample Size: Not explicitly stated how many individual samples were tested, but it covered levels from 0 to 1693 cells/µL for CD3+CD4+ cells and 0 to 3923 cells/µL for CD3+ cells.
- Data Provenance: Not specified.
- Method Comparison:
- Sample Size: 70 samples.
- Data Provenance: Not specified, but the context suggests these are human blood samples. The study was likely prospective to directly compare the new device with the predicate.
- Carryover Study:
- Sample Size: Not specified, but involves high and low cell count samples.
- Data Provenance: Not specified.
- Sample Stability:
- Sample Size: Not specified.
- Data Provenance: Not specified, but blood samples were used.
- Reagent Shelf-Life Stabilities:
- Sample Size: Not specified.
- Data Provenance: Not specified, but real-time stability studies imply laboratory-controlled experiments.
- External Evaluation:
- Sample Size: Not explicitly stated for this part, but it references "a wide panel" and "All of the method comparison results" which suggests it replicates or expands on the internal method comparison potentially with different samples or a larger set for the specific cell types mentioned.
- Data Provenance: "External site studies" implies data from a different laboratory or clinical setting than the manufacturer's. This would likely be a prospective comparison.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
This device is an automated cell counter, not an interpretative AI/diagnostic imaging device. Therefore, the concept of "experts" establishing a "ground truth" for interpretation, as would be the case for radiologists, does not directly apply here.
The "ground truth" for comparison for the Cyto-Cal™ Count Tubes is established by the predicate device, BD Trucount Tubes, which is also an automated cell counting system. The performance of the predicate device serves as the reference, and the new device is evaluated against its readings rather than human expert interpretations.
4. Adjudication method for the test set
Not applicable in the traditional sense for an automated cell counter. The comparison is directly between the new device and the predicate device. There is no human interpretation or adjudication involved to establish a "ground truth" for each sample in the way it would be for a diagnostic image.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
Not applicable. This device is an automated in vitro diagnostic used for absolute cell counts. It does not involve human readers for interpretation, nor does it provide AI assistance to human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, the studies described (Precision, Dilution Recovery, Method Comparison, Carryover, Stability) are all standalone performance evaluations of the Thermo Scientific Cyto-Cal™ Count Tubes without human intervention in the counting process itself. The device is designed to operate as an automated system.
7. The type of ground truth used
The ground truth used for comparison is the results obtained from the predicate device, BD Trucount Tubes. This is a comparative method study, where the new device's performance is gauged by its agreement with an already legally marketed and accepted device.
8. The sample size for the training set
The document does not mention "training set" or "training data" as it would for a machine learning model. This is a traditional in vitro diagnostic device, not an AI/ML algorithm that requires a separate training phase. The "development" of the device would involve internal testing and optimization that might use many samples, but it's not structured as a "training set" in the AI sense.
9. How the ground truth for the training set was established
Not applicable, as there is no mention of a "training set" in the context of an AI/ML algorithm.
§ 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.”