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The OScout™ Lab is a quantitative multi-parameter automated hematology analyzer intended for in vitro diagnostic use in screening patient populations 18 years and older found in clinical laboratories and point-of-care (POC) settings. The QScout Lab is used with the QScout RLD test to enumerate and classify the following parameters in venous K2/K3EDT A whole blood:

• White blood cell count (WBC)
• · Neutrophils (NEUT#)
• · Lymphocytes (LYMPH#)
• · Monocytes (MONO#)
• · Eosinophils (EOS#)
• · Basophils (BASO#)
• · Immature Granulocytes (IG#)
• · Percent Neutrophils (NEUT%)
• Percent Lymphocytes (LYMPH%)
• · Percent Monocytes (MONO%)
• · Percent Eosinophils (EOS%)
• · Percent Basophils (BASO%)
• · Percent Immature Granulocytes (IG%)
• · Neutrophil to Lymphocyte Ratio (NLR)

The QScout™ system is intended for in vitro diagnostic use in screening patient populations 18 years and older found in clinical laboratories and point-of-care (POC) settings. It includes the QScout Lab analyzer, the QScout RLD (Rapid Leukocyte Differential) test, software, and handheld barcode scanner. The QScout system reports white blood cell count and neutrophil to lymphocyte ratio and enumerates and classifies six white blood cell types including immature granulocytes.
The QScout RLD test includes a microfluidic chamber of predetermined volume containing a dried reagent of organic compounds to stain and fluoresce white blood cells. Once venous whole blood is transferred to the QScout RLD test, white blood cells mix with the reagent. The QScout RLD test is inserted into the QScout Lab, a quantitative multi-parameter automated hematology analyzer, where an optical imaging system takes images of the test chamber. A machine vision algorithm identifies cells from the images in real time. When analysis is complete, the results are displayed on the screen and can be printed.

Here's a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided FDA 510(k) summary for the QScout Lab and QScout RLD.

Note: The provided document primarily focuses on demonstrating substantial equivalence to a predicate device through various performance studies (method comparison, repeatability, reproducibility, detection limits, linearity, interference, stability, and flagging studies for clinical sensitivity). It does not explicitly define a single, overarching "acceptance criteria" table with pre-defined thresholds for all parameters, but rather implicitly defines acceptance through CLSI guidelines and successful outcomes of the tests. The "reported device performance" is the results shown in the tables.

1. Table of Acceptance Criteria and the Reported Device Performance

As noted above, a single clear table of acceptance criteria with numerical thresholds is not presented. Instead, acceptance is demonstrated by meeting the "pre-defined acceptance criteria" for various studies, often referencing CLSI standards. The reported device performance is provided in the tables and textual summaries of each study.

Here's a synthesized table based on common analytical performance metrics found in the document:

2. Sample Sizes Used for the Test Set and the Data Provenance

• Method Comparison Study:

  • Sample Size: 396 K₂EDTA/K₃EDTA whole blood samples.
  • Data Provenance: Conducted at a clinical laboratory and seven point-of-care sites. Included normal and pathological samples (allergic reaction, anemia, infections, etc.). Implying a mix of retrospective and prospective, likely prospectively collected for the study purposes but from existing patient populations. No specific country of origin is mentioned, but implicitly US given the FDA submission.

• Repeatability Study:

  • Sample Size: 12 samples for WBC <4 x10³/μL range, 19 samples for WBC ≥4 x10³/μL range. Each sample measured at least 20 times (20-31 replicates).
  • Data Provenance: K₂EDTA/K₃EDTA whole blood samples. No specific country mentioned.

• Reproducibility Study:

  • Sample Size: Tri-level quality control material (Low, Normal, High). A total of 60 measurements per level per site (3 sites x 2 operators/site x 2 runs/day x 6 replicates/run x 5 days = 360 measurements per level across all sites).
  • Data Provenance: Quality control material. Multi-center study (3 sites). No specific country mentioned.

• Detection Limits Studies:

  • Limit of Blank: 5 centrifuged venous blood samples, each assayed 6 times on 2 QScout Labs and 2 RLD lots (total 60 measurements for WBC per RLD lot).
  • Limit of Detection: 5 low WBC concentration samples, each assayed 6 times on 2 QScout Labs and 2 RLD lots (total 60 measurements for WBC per RLD lot).
  • Limit of Quantitation: 4 low WBC concentration samples, each assayed 5 times on 2 QScout Labs and 2 RLD lots (total 40 measurements for WBC per RLD lot).
  • Data Provenance: Venous whole blood samples (diluted or depleted). No specific country mentioned.

• Linearity Studies:

  • Sample Size: 2 venous whole blood samples manipulated to create 10 concentrations. Each concentration measured at least 4 times.
  • Data Provenance: Venous whole blood samples. No specific country mentioned.

• Analytical Specificity/Interference Studies:

  • Sample Size: Not explicitly stated as a total number of samples, but tests were performed using samples spiked with various interferents.
  • Data Provenance: No specific country mentioned.

• Sample Stability:

  • Sample Size: 11 venous whole blood samples (6 normal, 5 around medical decision levels).
  • Data Provenance: Venous whole blood samples. No specific country mentioned.

• QScout RLD Test Stability & QScout BCS Stability:

  • Sample Size: 6 lots of RLD tests for real-time stability; 3 lots of BCS for shelf-life stability.
  • Data Provenance: Manufacturing lots of the device components.

• Clinical Sensitivity/Flagging Study:

  • Sample Size: 200 samples.
  • Data Provenance: Samples from one clinical laboratory and seven point-of-care sites. Included distributional and morphological abnormal samples. Implicitly retrospective collection (existing samples with known abnormalities) or prospective collection of samples with known characteristics. No specific country mentioned.

• Reference Interval Study:

  • Sample Size: 265 apparently healthy adults (139 female, 126 male).
  • Data Provenance: Venous whole blood samples from healthy adults (≥ 18 years). No specific country mentioned.

• Matrix Comparison Study (K2EDTA vs K3EDTA):

  • Sample Size: 40 paired samples.
  • Data Provenance: Venous whole blood samples. No specific country mentioned.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts

The document does not specify the number or qualifications of experts used to establish ground truth.

• For the Method Comparison Study, the QScout system was compared against a "predicate device" (Beckman Coulter UniCel® DxH 800 Coulter® Cellular Analysis System), which serves as the reference standard. The predicate device's output is assumed to be the "ground truth" for comparison purposes.
• For the Clinical Sensitivity/Flagging Study, the reference method was a "400-cell manual differential reference method." While this implies human experts (e.g., experienced medical technologists or hematopathologists) performed the manual differential, the number and specific qualifications of these experts are not provided.

4. Adjudication Method for the Test Set

The document does not describe any specific adjudication method (e.g., 2+1, 3+1) for resolving discrepancies in the test set.

• For the Method Comparison study, it's a comparison against a single predicate device output.
• For the Clinical Sensitivity/Flagging Study, it explicitly states a "400-cell manual differential reference method," implying that this manual method itself was considered the ground truth, rather than an adjudicated consensus of multiple readers.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, a multi-reader multi-case (MRMC) comparative effectiveness study comparing human readers with and without AI assistance was not conducted or reported in this 510(k) summary. This device is an automated hematology analyzer designed to perform cell counting and differentiation automatically, rather than to assist human readers in image interpretation. Its primary comparison is to a predicate automated device.

6. If a Standalone (i.e., Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, the performance data presented (Method Comparison, Repeatability, Reproducibility, Detection Limits, Linearity, Analytical Specificity, Stability) are all measurements of the standalone performance of the QScout system (the QScout Lab analyzer and QScout RLD assay) without human intervention in the analysis process itself. The data in Tables 1-9 represent the algorithm's output directly compared to reference methods or statistical performance metrics. The device is an automated analyzer, so its core function is algorithm-only.

7. The Type of Ground Truth Used

The ground truth varied depending on the study:

• Method Comparison Study: The output of the predicate device (Beckman Coulter UniCel® DxH 800 Coulter® Cellular Analysis System) was used as the reference/ground truth for comparison.
• Clinical Sensitivity/Flagging Study: A "400-cell manual differential reference method" was used as the ground truth. This is typically performed by highly trained laboratory professionals based on microscopic examination.
• Precision, Detection Limits, Linearity, Analytical Specificity, Stability Studies: These studies typically use predefined reference materials, spiked samples, or expected values based on known concentrations or manipulations of samples (e.g., diluted samples for low WBC, samples treated with specific interferents). The performance is evaluated against these known or expected values.
• Reference Interval Study: The ground truth for health was based on samples collected from apparently healthy adults, and the intervals were statistically derived from these measurements.

8. The Sample Size for the Training Set

The document does not provide information on the training set for the machine vision algorithm. The provided text is a 510(k) summary for device clearance, which focuses on validation studies against a predicate and clinical standards, not necessarily the development or training of the internal algorithms. This information would typically be considered proprietary and might be part of an internal V&V report, but not usually released in a public summary.

9. How the Ground Truth for the Training Set Was Established

Since information on the training set itself is not provided, the method for establishing its ground truth is also not described in this document. Given that the device uses a "machine vision algorithm to identify cells from the images in real time," it's highly probable that the training involved extensive datasets of annotated cell images where the cell types (neutrophil, lymphocyte, monocyte, etc.) were identified and labeled by human experts (e.g., highly experienced hematologists or medical technologists).

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