(30 days)
The QBC STAR™ Centrifugal Hematology System provides a diagnostic hematology profile on venous or capillary blood: hematocrit, hemoglobin, mean corpuscular hemoglobin concentration (MCHC), platelet count, white blood cell count, granulocyte count (% and number) and lymphocyte/monocyte count (% and number).
The QBC STAR™ Centrifugal Hematology System is a self-contained, whole blood automated hematology system. Testing can be performed on venous or capillary samples. All tests are performed in the QBC STAR™ Blood Collection Tube. The system is powered by a universal voltage internal power supply that plugs directly into an AC power source. The instrument is factory preset and does not require user calibration. The methodology of the QBC STAR centrifugal hematology system is based on electro-optical linear measurements of the discrete layers of packed blood cells in a microhematocrit-type tube. The cell layering results from density gradients formed during high-speed centrifugation of the blood. Nine primary hematology values, including, hematocrit, hemoglobin, mean corpuscular hemoglobin concentration (MCHC), white blood cell count, platelet count, granulocyte count (% and number) and lymphocyte/monocyte count (% and number) are derived. QBC hematology tests utilize precision-bore glass tubes pre-coated with potassium oxalate, acridine orange fluorochrome stain and an agglutinating agent. During high-speed centrifugation of the blood-filled tube, the cells form in packed layers, according to their density, around the float, which has descended into the red blood cells. The buffy coat is automatically scanned and fluoresence and absorbance readings are made to identify the expanded layers of differentiated cells. Volumes of these packed cell layers are then computed to obtain quantitative values for the listed parameters. On the QBC STAR system, the hematocrit, white blood cell counts and the platelet count are direct measurements of the cell lavers. The hemoglobin measurement is directly related to the density of the red blood cells and based on the depth of penetration of the float into the red blood cell layer. Mean Corpuscular Hemoglobin Concentration (MCHC) is a function of hemoglobin and hematocrit and is electronically calculated according to the standard equation (Hab/Hct x 100).
Here's an analysis of the provided text regarding the acceptance criteria and study for the QBC STAR™ Centrifugal Hematology System, formatted as requested:
Acceptance Criteria and Study for QBC STAR™ Centrifugal Hematology System
1. Table of Acceptance Criteria and Reported Device Performance
The provided document doesn't explicitly state quantitative "acceptance criteria" in a typical numerical format (e.g., "accuracy must be >95%"). Instead, the acceptance criteria are implicitly defined by demonstrating equivalent performance to the predicate device, the QBC™ AUTOREAD™ Plus Hematology System, for all measured parameters. The reported device performance is therefore the demonstrated equivalence.
| Acceptance Criteria Category | Specific Criteria (Implicit for Equivalence) | Reported Device Performance |
|---|---|---|
| Overall Performance | Equivalent performance to predicate device across all hematology parameters. | Validation through accuracy testing of venous and capillary samples showed equivalent performance to the previously cleared product. |
| Technical Equivalence | Modifications do not present new issues of safety and effectiveness. | Modifications were assessed through risk analysis. Verification tests were performed. |
| Software Integrity | System software appropriately rejects or accepts processed samples. | Assessed. |
| Optical Component Function | Equivalence between new optical components and those of the previously cleared product. | Comparison of scans from multiple blood and control samples. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: Not explicitly stated. The document mentions "multiple blood and control samples" and "venous and capillary samples."
- Data Provenance: Not explicitly stated. Given the context of a 510(k) submission to the FDA, it is highly likely the studies were conducted in the USA, but this is not confirmed. The document does not specify if the data was retrospective or prospective.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
Not applicable. This type of device (hematology analyzer) typically uses established laboratory reference methods or predicate devices for ground truth comparison, rather than human experts interpreting results. The predicate device's performance serves as the benchmark for equivalence.
4. Adjudication Method for the Test Set
Not applicable. As described above, human expert adjudication is not typically used for establishing ground truth for automated hematology analyzers. The device's measurements are directly compared against established reference methods or the predicate device's results.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not done. This type of study evaluates human reader performance, typically in imaging diagnostics, and is not relevant for an automated hematology analyzer.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, the study demonstrates the standalone performance of the QBC STAR™ Centrifugal Hematology System. This device is an automated hematology analyzer, meaning it operates without human intervention in the interpretation or direct measurement of results from a sample. Its performance is evaluated independently of a human operator's judgment apart from proper sample collection and loading.
7. The Type of Ground Truth Used
The ground truth was established by:
- Predicate Device Performance: The QBC™ AUTOREAD™ Plus Hematology System's performance served as the primary benchmark for demonstrating substantial equivalence.
- Established Laboratory Reference Methods: Although not explicitly detailed, "accuracy testing" usually implies comparison to well-established and validated laboratory methods for hematology parameters.
8. The Sample Size for the Training Set
Not explicitly stated. The document focuses on verification testing and comparison to a predicate device, rather than detailing a separate "training set" in the context of machine learning. The device's algorithms are pre-programmed and based on physical principles of blood separation and optical measurement, not on machine learning models that require a distinct training set in the modern sense.
9. How the Ground Truth for the Training Set Was Established
Not applicable in the typical machine learning sense. The "ground truth" for developing the underlying algorithms and measurement principles of the QBC STAR™ (and its predicate) would have been established through:
- Known physical properties of blood cells: Density, size, and fluorescent properties.
- Extensive laboratory testing and empirical data: To refine the algorithms that convert optical measurements to cell counts and other hematology parameters.
- Clinical correlation: Ensured the device's measurements correlated with patient health status and clinical needs.
The document indicates that existing algorithms from the predicate device were likely re-used or adapted ("A series of numerical algorithms convert the volume of measured cell material in each layer to an equivalent cell count," identical description for both devices in Table 1). Therefore, the "training" (development and refinement) of these algorithms would have occurred during the development of the predicate device and potentially minor adjustments during the development of the QBC STAR system.
§ 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.”