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The MD 800 is a multi-parameter, automated hematology analyzer used to perform in vitro diagnosis of peripheral human blood in clinical laboratories.

The MD 800 reports on the following parameters:

White Blood Cells (Leukocytes) WBC
Red Blood Cells (Erythrocytes) RBC
Hemoglobin Concentration Hgb
Hematocrit (relative volume of erythrocytes) Hct
Mean Corpuscular (erythrocyte) Volume MCV
Mean Corpuscular (erythrocyte) Hemoglobin MCH
Mean Corpuscular (erythrocyte) Hemoglobin Concentration MCHC
Red Blood Cell (erythrocyte volume) Distribution Width RDW
Platelet or Thrombocyte Count Plt
Mean Platelet (thrombocyte) Volume MPV
Lymphocyte (number) LY#
Lymphocyte (percent of WBC) LY%
Monocyte (number) MO#
Monocyte (percent of WBC) MO%
Basophil (number) BA#
Basophil (percent of WBC) BA %
Neutrophil (number) NE#
Neutrophil (percent of WBC) NE%
Eosinophil (number) EO#
Eosinophil (percent of WBC) EO %

The MD 800 is a quantitative analyzer of peripheral human blood for in vitro diagnostic use in clinical laboratories. It performs an automated complete blood count (CBC) and a leukocyte differential on peripheral human blood. A sample volume of 20 uL of whole blood is required. The instrument provides a printed report on 20 parameters. The MD 800 consists of five components: (1) A blood analysis instrument, (2) A reagent dispensing unit and four reagents, (3) Calibration and control reagents, (4) Probeclenz™, a cleaning liquid, and (5) A standard, off-the-shelf high resolution printer. The instrument uses precise, motorized syringes, electronically controlled valves, cuvettes, transducer chambers, connective tubing and wiring, a communications panel, and a computer and related software program to analyze the blood sample.

The MASCOT MD Hematology Analyzer Model MD 800 is an automated differential blood cell counter. The provided document details its technical specifications, principle of operation, and studies conducted to demonstrate its substantial equivalence to a legally marketed predicate device, the Coulter Model STKS.

Here's an analysis of the acceptance criteria and the studies that prove the device meets them:

1. A table of acceptance criteria and the reported device performance

The acceptance criteria are primarily defined by the precision and linearity specifications, and the device's performance is listed alongside its predicate device (Coulter STKS) in Figure 8-1. The document asserts that the MD 800 performs within the normal and expected range for automated hematology instruments and is comparable to the Coulter STKS.

Acceptance Criteria & Reported Performance (from Figure 6-1 & 8-1)

The table indicates that the MD 800 consistently meets its own stated "MD 800 SPECIFICATIONS" for precision and linearity. For comparative purposes, the Coulter STKS often boasts tighter specifications. However, the study aims to show substantial equivalence, not necessarily superior performance in every metric. The study's conclusion is that the MD 800's results "fall well within the accepted range for that parameter" and are "comparable" to the Coulter STKS.

2. Sample sizes used for the test set and the data provenance

• Study #1 (Comparison Test):
  • Initial Sample Size: 215 excess patient whole blood samples.
  • WBC Differential Count Portion: Reduced to 129 samples after eliminating those with morphologic positive results, as recommended by NCCLS H20-A.
  • Data Provenance: Retrospective, from Lawrence & Memorial Hospital in New London, Connecticut, during 1997. Samples were "excess patient recently drawn whole blood samples."
• Study #2 (Sensitivity Study):
  • Sample Size: All 215 excess blood samples initially selected for Study #1 were used.
  • Data Provenance: Retrospective, from Lawrence & Memorial Hospital in New London, Connecticut.
• Study #3 (Field Use Correlation Study):
  • Total Sample Size: 147 whole human blood samples.
    • 57 samples from Norwalk General Hospital, Norwalk, Connecticut.
    • 40 samples from Lawrence & Memorial Hospital, New London, Connecticut.
    • 50 samples from Children's Medical Associates, P.C. (a pediatric clinic) in Ansonia, Connecticut.
  • Data Provenance: Prospective (implied, as laboratories were instructed to analyze "excess fresh human blood samples... until they had each analyzed forty or more samples, and record the results for each over a period of days"). The data came from three different U.S. clinical laboratory sites.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

• Number of Experts: For Study #1 and #2, two technicians performed manual WBC differential counts.
• Qualifications of Experts: The document refers to them as "clinical laboratory workers" and "technicians." No specific qualifications (e.g., years of experience, certification) other than their role in a clinical laboratory are provided.

4. Adjudication method for the test set

• Adjudication Method: For ground truth in Study #1 and #2, the results from the two technicians who performed manual WBC differential counts were averaged. This minimizes the effects of human error.

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

There was no MRMC comparative effectiveness study done involving human readers and AI assistance. This device is an automated hematology analyzer, not an AI-assisted diagnostic tool for human interpretation. The comparison is between the MD 800's automated results and manual counts, and between the MD 800 and another automated device (Coulter STKS).

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

Yes, the studies primarily assessed the standalone performance of the MD 800. The device itself is an automated system providing parameters. While human operators are involved in initiating the test and handling reports, the core analysis and parameter generation are done by the algorithm (hardware and software) without human-in-the-loop diagnostic decision-making during the analysis process itself. The manual differential counts served as a reference (ground truth) for evaluating the automated system's performance.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

The ground truth for the studies was primarily:

• Manual Reference Method (Expert Consensus/Manual Count): For WBC differential counts and morphological/distributional abnormalities. This involved two "clinical laboratory workers" or "technicians" performing manual counts, and their averaged results were used as ground truth.
• Predicate Device (Coulter STKS): For comparison of precision, accuracy, and overall parameter measurements across various hematological parameters. The Coulter STKS served as a reference standard for automated performance.

8. The sample size for the training set

The document does not specify a separate training set size. The description focuses entirely on validation studies against predicate devices and manual methods. Given the technology (impedance, spectrophotometry, and a mathematical algorithm called "Expectation Maximization" for processing signals), it's plausible the algorithm was developed and refined using internal datasets, but no details are provided here.

9. How the ground truth for the training set was established

As no explicit training set is mentioned or detailed, the method for establishing its ground truth is not provided in this document. If the "patented mathematical algorithm named Expectation Maximization (EM)" had parameters tuned or learned, the method for establishing ground truth for that process is omitted from this summary.

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