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The COULTER® Z2 instrument may be used for in vitro diagnostic use to determine the human erythrocyte concentration (Red Cell Count or RBC), leukocyte concentration (White Cell Count or WBC) and thrombocyte concentration (Platelet Count or Plt). In addition, the COULTER Z2 also provides the mean erythrocyte volume (Mean Cell Volume or MCV) and the mean thrombocyte volume (Mean Platelet Volume or MPV).

The COULTER Z2 is a general purpose dual threshold particle counter and sizer designed to count and size particles, suspended in an aqueous electrolyte solution, within the range of 1 to 120 um equivalent spherical diameter. The instrument is designed for both biological and industrial use. As with the predicate devices, the COULTER Z2 utilizes the Coulter principle for the enumeration and sizing of blood cells. The same reagent system, composed of an isotonic diluent, lytic reagent to lyse red blood cells for WBC measurement and instrument cleaner, is used on COULTER STKS, Z1, and Z2 instruments. The COULTER STKS, Z1, and Z2 instruments are capable of determining the human erythrocyte concentration (Red Cell Count or RBC), leukocyte concentration (White Cell Count or WBC) and thrombocyte concentration (Platelet Count or Plt). In addition, like the COULTER STKS, the COULTER Z2 also provides the mean erythrocyte volume (Mean Cell Volume or MCV) and the mean thrombocyte volume (Mean Platelet Volume or MPV). Both the COULTER Z1 and the Z2 instruments contain a hydraulic metering station built into the electronics main unit, measure a restricted range of particle sizes (within the range 1 to 120 µM) and utilize surface-mount technology. Operator-adjustable controls are accessible by means of a keyboard data terminal.

Here's a breakdown of the acceptance criteria and study information for the COULTER® Z2 Analyzer, based on the provided text:

Acceptance Criteria and Device Performance for COULTER® Z2 Analyzer

The provided document describes the COULTER® Z2 Analyzer and its substantial equivalence to predicate devices, focusing on the added parameters of Mean Cell Volume (MCV) and Mean Platelet Volume (MPV). The "acceptance criteria" are implicitly defined by the reported performance metrics (imprecision and accuracy) that demonstrate its equivalence to already commercially distributed hematology analyzers.

1. Table of Acceptance Criteria and Reported Device Performance

Since explicit "acceptance criteria" are not given in numerical ranges (e.g., "CV% must be <= X"), the table below reflects the reported performance data from the "Summary of Performance Data" section, implying these values met the necessary standards for substantial equivalence. The predicate device performance is not explicitly detailed in the provided text for a direct comparison in terms of numerical criteria, but the study asserts "substantial equivalence" through these results.

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

• Sample Size for Test Set:
  • For Reproducibility (Imprecision) analysis: The table for "COULTER Z2 Analyzer Imprecision Analysis by Reproducibility" does not explicitly state the number of samples or runs, but presents mean, SD, and CV% data, typically derived from multiple measurements on a set of samples.
  • For Accuracy analysis (Compared Samples): N = 31 samples.
• Data Provenance: The document does not specify the country of origin of the data or whether the study was retrospective or prospective. It is a submission to the US FDA, so it is likely US-based, but this is not explicitly stated.

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

The document does not mention the use of experts or their qualifications for establishing ground truth for the test set. The study focuses on comparing the device's results to a reference method, which is implicitly the predicate device or a recognized standard for cell counting.

4. Adjudication Method for the Test Set

The document does not describe any adjudication method. This type of study (hematology analyzer performance) typically relies on direct comparison to reference methods or predicate devices rather than expert adjudication.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This study is for an automated cell counter, not an interpretative diagnostic aid for human readers. Therefore, the concept of "how much human readers improve with AI vs without AI assistance" is not applicable here.

6. If a Standalone (algorithm only without human-in-the-loop performance) was done

Yes, the study describes the standalone performance of the COULTER® Z2 Analyzer. The data presented for imprecision and accuracy are measurements directly from the device, without human intervention in the result generation or interpretation to modify the output. The device itself is described as "semi-automated," implying some human interaction for sample loading and operation, but the performance data presented are inherent to the device's measurement capabilities.

7. The Type of Ground Truth Used

The "ground truth" for this study appears to be established by comparison to the predicate devices (COULTER® Z1 and COULTER® STKS analyzers) and/or a reference method or standard laboratory measurements. The summary states, "Equivalence is demonstrated through compared sample accuracy and imprecision results," implying that the Z2's measurements were compared against established, acceptable values, likely from the predicate devices which were already cleared. The specific "ground truth" (e.g., gold standard manual counting, another validated automated system) for the compared samples is not explicitly detailed beyond being "compared samples."

8. The Sample Size for the Training Set

The document does not specify a separate "training set" or its sample size. This is common for medical devices approved through the 510(k) pathway, especially for analytical devices where performance is characterized through reproducibility and accuracy against predicate devices or reference methods, rather than machine learning model training.

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

Since no explicit training set is mentioned in the context of machine learning, there is no description of how ground truth for a training set was established. The performance evaluation focuses on the device's analytical capabilities through direct measurement and comparison.

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