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The D-Dimer Assay is for the quantitative determination of fibrin degradation products (D-Dimer) in human plasma. Measurement of D-Dimer is used as an aid in detecting the presence of intravascular coagulation and fibrinolysis. For in vitro diagnostic use only.

The Diazyme D-Dimer Calibrator Set is intended for use of the calibration of the Diazyme D-Dimer Assay only. For in vitro diagnostic use only.

The Diazyme D-Dimer Control Set is intended for use as quantitative quality controls for the Diazyme D-Dimer Assay only. For in vitro diagnostic use only.

Diazyme's D-Dimer Assay is based on a latex enhanced immunoturbidimetric assay. D-Dimer proteins in the sample bind to the specific anti-D-Dimer antibody, which is coated on latex particles, and causes agglutination. The degree of the turbidity caused by agglutination can be measured optically and is proportional to the amount of D-Dimer in the sample. The instrument calculates the D-Dimer concentration of a patient specimen by interpolation of the obtained signal of a 6-point calibration curve.

Here's a breakdown of the acceptance criteria and study information for the Diazyme D-Dimer Assay Kit, Diazyme D-Dimer Assay Calibrator Set, and Diazyme D-Dimer Assay Control Set, based on the provided 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

Note: The acceptance criteria are largely implied by comparing the new device's performance to the predicate device and recognized standards like CLSI guidelines. The predicate's correlation coefficient, slope, and intercept were against a different comparator (Asserachrom D-Dimer), so the Diazyme assay provides new comparison values against its chosen predicate (Roche Tina-Quant D-Dimer).

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

The provided document describes the test set as follows:

• Precision (Internal Study):
  • Plasma Samples: 3 levels of pooled citrated plasma (0.60 µg/mL, 2.41 µg/mL, 5.88 µg/mL FEU). Each level had 240 data points (duplicates over 20 days, likely 6 runs per day to get 240, though not explicitly stated as 'runs').
  • Control Samples: 3 levels of D-Dimer controls (0.97, 2.99, 7.47 µg/mL FEU). Each level had 240 data points.
• Precision (External Study):
  • Patient Samples: 4 different patient samples of citrated plasma (0.36, 1.06, 3.53, 7.20 µg/mL FEU).
  • Total Data Points: Not explicitly stated as a single number, but tested in duplicates with 2 runs per day over 5 nonconsecutive working days at three sites, with three lots of reagent, three lots of calibrators, three different operators, and three different instruments. This implies a significant number of data points per sample.
• Method Comparison:
  • Samples: A total of 128 citrated plasma samples (88 unique samples).
  • Range: D-Dimer ranging from 0.17 to 7.95 µg/mL FEU.
  • Provenance: Collected from an "intended target population" (Intensive Care Unit, Obstetrics, Trauma, Post-Operative, and Operating Room). Tested at the manufacturer site and two external clinical laboratories. This suggests a prospective or retrospective collection with prospective testing across multiple sites, with the data coming from diverse patient populations. No specific country of origin is mentioned, but "intended target population" and "external clinical laboratories" suggest it's likely within the US, where the submission is being made.
• Linearity: 11 levels of the D-Dimer linearity set.
• LOB, LOD, LOQ: Specimens with mean measured concentrations ranging from 0.02 to 0.93 were assayed.

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

For this type of in vitro diagnostic device (IVD) for quantitative determination of a biomarker (D-Dimer), the "ground truth" is typically the quantitative value obtained from testing the samples using a well-established, legally marketed reference or predicate method.

• Experts: Not applicable in the traditional sense of clinicians or radiologists reviewing images. The "ground truth" for the method comparison study was established by the Roche Tina-Quant D-Dimer (K062203), which is itself a legally marketed, validated assay.
• Qualifications: The "qualification" of the ground truth in this context relies on the regulatory approval and established performance of the predicate device. The analysis was performed by laboratory personnel following standard laboratory practices, as implied by the CLSI (Clinical and Laboratory Standards Institute) guidelines cited.

4. Adjudication Method for the Test Set

Adjudication methods (like 2+1, 3+1) are typically used in clinical studies involving interpretation of subjective data (e.g., imaging where multiple readers provide independent assessments).

• Adjudication Method: None was explicitly mentioned or implied. For quantitative biomarker assays, adjudication is not typically used. The accuracy of the Diazyme D-Dimer Assay was compared directly to the quantitative results from the predicate device (Roche Tina-Quant D-Dimer K062203) using statistical methods like regression analysis.

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

• MRMC Study: No, a Multi Reader Multi Case (MRMC) comparative effectiveness study was not done.
• Reason: This device is an in vitro diagnostic (IVD) assay that quantitatively measures D-Dimer in human plasma. It does not involve human readers interpreting images or data where AI assistance would be relevant. Therefore, the concept of "human readers improve with AI vs without AI assistance" does not apply to this device.

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

• Standalone Performance: The study inherently demonstrates standalone performance of the Diazyme D-Dimer Assay. The device is an automated, immunoturbidimetric assay for quantitative determination of D-Dimer. Its performance (precision, linearity, method comparison, LOB/LOD/LOQ, interference) was evaluated as a standalone analytical system, with the instrument calculating concentrations based on the optical measurements and its calibration curve. There is no human-in-the-loop performance described in the context of interpretation or output modification for this type of IVD.

7. The Type of Ground Truth Used

• Type of Ground Truth: The ground truth for the method comparison study was the quantitative D-Dimer concentration results obtained from the predicate device, Roche Tina-Quant D-Dimer (K062203). This is a common approach for IVD assays, where a new device's performance is gauged against an approved, established method.
  • For other performance metrics like LOB/LOD/LOQ and linearity, the ground truth is established by carefully prepared standards and dilutions, and statistical models applied to the measurements.

8. The Sample Size for the Training Set

• Training Set: The document does not describe a "training set" in the context of machine learning. This device is a biochemical assay, not an AI/ML-based device that requires a separate training set for algorithm development.
  • However, the calibration curves are established using a 6-point calibration curve (stated in Assay Principle). The Diazyme D-Dimer Calibrator Set consists of 5 calibrators plus saline (Cal 0). These calibrators are used to "train" the instrument to accurately translate turbidity measurements into D-Dimer concentrations for each assay run.

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

• As explained above, there is no "training set" for an AI/ML algorithm.
• For the calibration curve, the "ground truth" concentrations of the calibrator set are established during the manufacturing process of the Diazyme D-Dimer Calibrator Set. This process involves precise formulation and validation of the D-Dimer concentrations in each calibrator level. These assigned values are then used by the instrument to generate the standard curve against which patient samples are measured.

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