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510(k) Data Aggregation
(270 days)
The DxH 520 is a quantitative, multi-parameter, automated hematology analyzer for in vitro diagnostic use in clinical laboratories and physician's office laboratories. It is used to identify the normal patient with normal system-generated parameters from patients with abnormal parameters and/or flags that require additional studies.
The DxH 520 identifies and enumerates the following parameters: WBC, RBC, HGB, HCT, MCV, MCH, MCHC, RDW, RDW-SD, PLT, MPV, LY%, LY#, MO%, MO#, NE%, EO%, EO#, BA%, BA# in whole blood samples (venous and capillary) collected in K2EDTA and K3EDTA anticoagulants, and prediluted whole blood.
The instrument is for use in adult and pediatric populations, including neonates.
The DxH 520 instrument provides a complete blood count (CBC with Five Part Differential (5PD)). Blood specimens are processed using a Closed Vial sampling method as default and have the option to run as Open Vial per operator selection.
RBC, WBC and PLT cell counts and sizes are determined using the Coulter Principle (impedance). The WBC 5 part differential is determined using a combination of the impedance WBC data and the direct optical measurement (Axial Light Loss - ALL) using a blue LED focused through the WBC aperture. With the addition of the DxH 500 Series Lyse, the RBCs are lysed and the released hemoglobin is converted into stable Oxyhemoglobin (or Carboxyhemoglobin, if present). The resulting complex is then measured by spectrophotometry.
The data obtained from the counting, sizing, optical and hemoglobin measurements is processed to create the DxH 520 hematological measurement that the device reports. Raw information is digitized from all analytical modules and passed to an embedded computer processing. Algorithms using dynamic gates to differentiate WBC subpopulations and flagging are performed within the embedded computer.
Controls and calibrators are used to monitor the performance of the instrument.
The compact bench top design of the DxH 520 will benefit small laboratories where bench space is limited. The integrated color display with graphical icon based user interface is intended to facilitate ease of use and operator training. The small bench-top DxH 520 instrument utilizes fully featured integrated software usually found on larger instrumentation.
This document describes the premarket notification for the Beckman Coulter DxH 520 Hematology Instrument (K181475). The information provided is based on the "Performance Summary" table (Table 7) on pages 14-15 of the document.
1. Table of Acceptance Criteria and Reported Device Performance
| Study/Parameter | Acceptance Criteria/Guidance | Reported Device Performance |
|---|---|---|
| Measurement Procedure Comparison | Comparison to the predicate DxH800 for CBC and differential values (clinical and small lab/POL sites). Comparison to manual microscopy (reference method) for WBC differential. Relevant FDA Guidances: "Special Controls Guidance Document: Premarket Notifications for Automated Differential Cell Counters for Immature or Abnormal Blood Cells - Accuracy (Section 8)"; Relevant Standards: CLSI H26-A2, CLSI H20-A2, CLSI GP41-A6, CLSI GP42-A6. | The results support the accuracy claims for all parameters. The data showed substantial equivalency of the CBC and DIFF parameters to the DxH 800 predicate system at large clinical laboratories (including cancer centers) and at small laboratories with less experienced operators. The DxH 520 is substantially equivalent to the reference method (manual slides) for the differential proportional parameters. |
| Precision | Assessment of long-term precision (repeatability and reproducibility) for all parameters. All whole blood repeatability acceptance criteria were met. All pre-dilute repeatability parameters met all requirements. Relevant FDA Guidance: "Special Controls Guidance Document: Premarket Notifications for Automated Differential Cell Counters for Immature or Abnormal Blood Cells - Precision (Section 9)"; Relevant Standards: CLSI H26-A2, CLSI EP05-A3, CLSI H20-A2. | The long-term precision (repeatability and reproducibility) meets the requirements as specified for all parameters. All whole blood repeatability acceptance criteria for all parameters were met. All pre-dilute repeatability parameters met all requirements. The pre-dilute precision is highly dependent on the operator's preparation of the dilutions. The Operator to Operator Variability of pre-dilute and whole blood for between operator and within specimen are provided as performance characteristics only. The variability at small laboratories does not invalidate the results as the same users participated in the accuracy study where all specifications were met. The pre-analytical handling of samples in a POL setting provides accurate analysis on the DxH 520 and has low impact on operator variability. |
| Clinical Sensitivity (Flagging) | Assess clinical sensitivity and specificity of overall flagging on the DxH 520 compared to the accepted reference method for differential determination (manual slide counts). Relevant FDA Guidance: "Special Controls Guidance Document: Premarket Notifications for Automated Differential Cell Counters for Immature or Abnormal Blood Cells - Performance (Section 10)"; Relevant Standards: CLSI H26-A2, CLSI H20-A2, CLSI EP12-A2, CLSI GP41-A6, CLSI GP42-A6. | The false negative samples were reviewed by the Beckman Coulter Medical Director for their potential clinical impact. There were no false negatives generated by blasts in this data set. Based on the Medical Director assessment, none of the false negatives that occurred would have compromised patient diagnosis and treatment. The overall rate of FN was 13.5% with a sensitivity of 86.5% and specificity of 68.7%. |
| Linearity | Demonstrating that reported results are directly proportional to the measurand concentration for WBC, RBC, HGB, and PLT. Relevant FDA Guidance: "Special Controls Guidance Document: Premarket Notifications for Automated Differential Cell Counters for Immature or Abnormal Blood Cells - Linearity (Section 11)"; Relevant Standards: CLSI H26-A2, CLSI EP06-A. | The WBC, RBC, Hgb, and Plt parameters met the linearity specifications. |
| Carryover | Verification of carryover for WBC, RBC, HGB, and PLT. Relevant FDA Guidance: "Special Controls Guidance Document: Premarket Notifications for Automated Differential Cell Counters for Immature or Abnormal Blood Cells - Carryover (Section 12)"; Relevant Standard: CLSI H26-A2. | All carryover testing for WBC, differential, RBC, PLT, and Hgb met the specification with 95% confidence on the upper limit. |
| Detection Capability (LoB, LoD, LoQ) | Assess performance detection capability limits using precision profiles for Lower Limit of Detection (LLoD) and Lower Limit of Quantitation (LLoQ) for WBC, RBC, HGB, and PLT measurands. Relevant Standards: CLSI H26-A2, CLSI EP17-A2. | Results for the detection capability of each instrument for the WBC, RBC, Hgb, and Plt parameters were within the specifications. |
| Specimen Stability | Assess stability: long-term for drift over time at RT and refrigerated, and pre-dilute for drift over 90 minutes. Relevant Standards: CLSI H26-A2, CLSI EP25-A. | All parameters met the corresponding requirements for whole blood specimen stability at 8hrs and 24hrs. Results were within the specifications. All parameters met the corresponding requirements for Pre-dilute Stability claim of 15 minutes. |
| Interfering Substances | Determine the level of lipemia, bilirubin, leukocytes, and hemoglobin that affects hematology results. Relevant Standards: CLSI H26-A2, C56-A. | The concentrations indicated for Lipemia (62.5 mg/dl), Conjugated Bilirubin (40mg/dl), Unconjugated Bilirubin (20mg/dl), and Hemoglobin (200 mg/dl) are the highest concentrations that did not interfere with the CBC parameters. For Leucocytes (100 x10^3/uL), this is the highest concentration that did not interfere with the Hemoglobin parameter. |
| Equivalency | Demonstrate pre-analytical and within-instrument equivalency for Pre-Dilute vs. Whole Blood, K2 and K3 EDTA, and all sampling modes. Relevant Standard: CLSI H26-A2. | In all sampling modes, the results demonstrated equivalency for all parameters tested and performance was within the specifications of the instrument. |
| Reference Intervals | Establish reference intervals for adult males/females and pediatric (0 days - 21 years) males/females combined. Relevant FDA Guidance: "Special Controls Guidance Document: Premarket Notifications for Automated Differential Cell Counters for Immature or Abnormal Blood Cells - Reference Values (Section 14)"; Relevant Standard: EP28-A3c. | The adult reference interval was established on the DxH520 system for all parameters and included in the product labeling and software. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state the exact sample sizes for each test set within the "Performance Summary" table. However, it indicates:
- Measurement Procedure Comparison: Samples were collected from "clinical sites and small laboratory / physician office laboratory sites." This suggests prospective collection of real-world patient samples.
- Precision: Three studies were conducted:
- Long Term Precision: Clinical and Small Laboratory/POL Sites.
- Short term precision: Whole blood Repeatability.
- Short term precision: Pre-Dilute Repeatability.
Again, implying real-world or simulated patient samples.
- Clinical Sensitivity: Not directly specified, but false negative samples were reviewed.
- Other studies (Linearity, Carryover, Detection Capability, Specimen Stability, Interfering Substances, Equivalency): The description of these studies suggests the use of various control materials, diluted samples, and potentially spiked samples, rather than a broad range of patient samples.
Data Provenance: The studies for accuracy and precision were conducted at "clinical sites and small laboratory / physician office laboratory sites," indicating a mix of real-world clinical environments. The document does not specify the country of origin of the data, but it is a US FDA 510(k) submission, suggesting primarily US-based evaluation. The nature of the studies implies prospective data collection for validation tests.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- Measurement Procedure Comparison (WBC Differential): The reference method used was "manual microscopy." While "experts" are inherently involved in manual microscopy for differential counts, the number of experts and their specific qualifications (e.g., "radiologist with 10 years of experience") are not explicitly stated in this document.
- Clinical Sensitivity (Flagging): "The false negative samples were reviewed by the Beckman Coulter Medical Director for their potential clinical impact." This indicates one expert (a Medical Director) was involved in reviewing clinical impact for false negatives. Their specific qualifications are not detailed beyond being a "Medical Director."
4. Adjudication Method for the Test Set
The document does not explicitly describe a formal adjudication method (like 2+1 or 3+1) for establishing ground truth for the test sets.
- For the measurement procedure comparison, the "manual microscopy" is presented as the reference method. It's implied this is the accepted ground truth for WBC differential without further adjudication details.
- For clinical sensitivity, the "Beckman Coulter Medical Director" reviewed false negative samples. This indicates a single expert review, not a consensus-based adjudication, specifically for the clinical impact of false negatives, not for establishing all ground truths.
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
No. The DxH 520 is an automated hematology instrument, not an AI-assisted diagnostic tool that involves human readers interpreting images. The studies performed were to validate the performance of the automated instrument itself against predicate devices and reference methods. Therefore, an MRMC comparative effectiveness study involving human reader improvement with/without AI assistance is not applicable and was not performed.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was Done
Yes. The entire submission for the DxH 520 Hematology Instrument is focused on its standalone performance as an automated analyzer. The "Measurement Procedure Comparison" directly compares the device's numerical results to a predicate device and manual microscopy, demonstrating its performance without human intervention in the primary measurement. The "Clinical Sensitivity" study evaluates the device's flagging algorithm performance alone.
7. The Type of Ground Truth Used
The types of ground truth used include:
- Expert Consensus (implied): "Manual microscopy" for WBC differential is considered the reference method and implicitly involves expert interpretation.
- Predicate Device Data: For CBC and differential values, the predicate DxH 800 served as a comparative ground truth to establish substantial equivalence.
- Pre-defined Specifications/Standards: For linearity, carryover, detection capability, stability, and interfering substances, the ground truth is established by recognized standards (e.g., CLSI guidelines) or internal specifications against which the device's measurements are assessed.
- Medical Director Review: For assessment of clinical impact of false negatives, a Medical Director's review served as a form of expert-determined ground truth for clinical relevance.
8. The Sample Size for the Training Set
The document does not provide information regarding a "training set" or its sample size. This is typical for an instrument validation submission of this nature where the focus is on the performance of a fully developed device, rather than the development and training of a machine learning algorithm. The "algorithms using dynamic gates to differentiate WBC subpopulations and flagging" are mentioned as being performed within the embedded computer, but details of their development or training data are not included in this summary.
9. How the Ground Truth for the Training Set Was Established
Since no information on a "training set" is provided, the method for establishing its ground truth is also not available in this document.
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