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The QStat Cartridge is a multi-channel cartridge that provides semi-quantitative indications of the coagulation and clot lysis state of a 3.2% citrated venous or arterial whole blood sample using the Quantra Hemostasis Analyzer. The QStat Cartridge includes tests to assess coagulation via the intrinsic and extrinsic pathways and includes a test with tranexamic acid to evaluate clot lysis characteristics.

The OStat Cartridge is intended for in vitro diagnostic use by trained professionals at the point-of-care and in clinical laboratories to evaluate the viscoelastic properties of whole blood by means of the following functional parameters: Clot Time (CT), Clot Stiffness (CS), Fibrinogen Contribution to Clot Stiffness (FCS), Platelet Contribution to Clot Stiffness (PCS), and Clot Stability to Lysis (CSL).

The QStat Cartridge is indicated for the evaluation of blood coagulation and clot lysis in patients age 18 years and older to assess possible hypocoagulable and hypercoagulable conditions in trauma and liver transplantation procedures.

Results obtained with the QStat Cartridge should not be the sole basis for patient diagnosis.

For prescription use only.

The QStat Cartridge is a single-use, multi-channel disposable plastic cartridge used with the Quantra Hemostasis Analyzer for the evaluation of blood coagulation and clot lysis. The measurements are performed in four test channels of the disposable cartridge which enable differential testing with different sets of reagents without the need for any reagent preparation or controlled pipetting. The cartridge utilizes a citrated evacuated blood collection tube filled with a patient whole blood sample The proprietary technology SEER Sonorheometry measures the evolution of shear modulus (i.e., clot stiffness) in all four channels as a function of time. The QStat Cartridge is intended for use in patients 18 years or older by professionals in a hospital setting (point of care or laboratory) to assess possible hypocoagulable and hypercoagulable conditions in trauma and liver transplantation procedures.

Each QStat Cartridge is pre-filled with lyophilized reagent beads individually sealed in an airtight pouch. After a QStat Cartridge is removed from its primary packaging, it is inserted into the instrument dock. A whole blood sample, collected in a 3.2% sodium citrate anticoagulant blood collection tube (minimum volume 2.7 mL), is attached directly to the cartridge and the test is initiated using the touch screen interface on the Quantra Hemostasis Analyzer. The cartridge is the only component of the Quantra System that is in direct contact with blood. The fluidic system within the instrument draws the sample into the cartridge where it is warmed to 37°C, aliquoted, introduced and mixed with the lyophilized reagents, and analyzed. When the test is complete, the cartridge is released from the dock to be disposed of in an appropriate biosafety sharps container.

The provided text is a 510(k) Premarket Notification from the FDA regarding the HemoSonics QStat Cartridge. The purpose of this submission is to expand the approved sample matrices to include arterial whole blood, in addition to the previously cleared venous whole blood.

The document does not detail a study proving the device meets acceptance criteria in the manner of an AI/ML device, as it concerns an in vitro diagnostic (IVD) device for measuring blood viscoelastic properties. Therefore, many of the requested items (e.g., number of experts, adjudication methods, MRMC study, training sets, ground truth establishment for AI/ML) are not applicable or described in this type of submission.

However, based on the information provided, we can infer some aspects relevant to device performance and the expansion of its indications for use.

Here's an analysis based on the provided text, addressing the applicable points and explaining why others are not relevant in this context:

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

The document defines the device's function and indications for use, but it does not provide a table of quantitative acceptance criteria and reported performance metrics for the device itself (e.g., accuracy, precision) in the context of an AI/ML algorithm evaluation. This is a 510(k) submission for a modification to an existing IVD, primarily focused on expanding the sample type. The "acceptance criteria" here refer to demonstrating substantial equivalence for the new claim (arterial blood).

What is reported is the intent to demonstrate equivalency between arterial and venous whole blood samples.

2. Sample size used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective)

The document states: "HemoSonics is submitting this Special 510(k) to demonstrate the equivalency of arterial and venous whole blood samples analyzed on the Quantra Hemostasis Analyzer with the QStat Cartridge in order to expand the sample matrices accepted on this system."

While it explicitly states the intent to perform a study for equivalency, the sample size and data provenance (country, retrospective/prospective) are not provided in this document. This information would typically be detailed in a separate study report submitted as part of the 510(k) supporting data, which is not included in this high-level summary.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience)

This question is typically relevant for interpretative devices, especially those using AI/ML where human expert interpretation forms the ground truth. For an IVD like the QStat Cartridge, which measures objective viscoelastic properties of blood, the "ground truth" is established by the accuracy and precision of the measurement itself against a reference method or known values, not by expert consensus on image interpretation. Therefore, this concept of "experts" to establish ground truth does not directly apply here.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set

Similar to point 3, adjudication methods are used in AI/ML performance studies where multiple human readers might disagree, and a consensus process is needed to establish ground truth. This is not applicable to a laboratory device that performs quantitative measurements.

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, an MRMC study was not done, nor would it be relevant for this type of device. MRMC studies are specific to evaluating the impact of AI assistance on human reader performance in tasks like image interpretation (e.g., radiology for diagnostic accuracy). The QStat Cartridge is an IVD that provides quantitative measurements of blood coagulation; it does not involve human "readers" interpreting cases in the sense of an AI-assisted diagnostic tool.

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

This question is also more applicable to AI/ML software. The QStat Cartridge is a physical device that performs measurements. Its performance is evaluated fundamentally in a standalone manner (the device's ability to accurately measure blood properties), but not in the context of an "algorithm only" as understood for AI/ML. The device generates quantitative parameters (Clot Time, Clot Stiffness, etc.). An "algorithm" within the device would process sensor data to yield these parameters, and the evaluation would focus on the accuracy of these output parameters.

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

For an IVD like the QStat Cartridge, the "ground truth" for its measurements would be established through:

• Reference Methods: Comparison of the QStat Cartridge's measurements (Clot Time, Clot Stiffness, etc.) against established, validated reference methods for measuring blood viscoelastic properties or related coagulation parameters.
• Known Samples: Testing with samples having known or characterized coagulation properties (e.g., calibrated controls, samples spiked with known substances).
• Clinical Correlation: While not a direct "ground truth" for the measurement itself, the clinical utility of the device's outputs is validated by correlating its results with patient clinical status or outcomes.

The document states the device provides "semi-quantitative indications" and its results "should not be the sole basis for patient diagnosis," indicating its role as a supportive diagnostic tool. The specific ground truth used for the arterial vs. venous equivalency study is not detailed here, but it would involve comparing measurements from paired arterial and venous samples from the same patient.

8. The sample size for the training set

This question is applicable to AI/ML models. Since this is an IVD device measuring physiological parameters, the concept of a "training set" for an AI model as typically distinguished from a "test set" does not apply in the same way. The device's measurement principles are based on established biophysical principles (SEER Sonorheometry), not on training a machine learning algorithm on a dataset. Any internal "algorithms" would be deterministic or model-based, not learned from data in the AI sense.

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

Not applicable, as explained in point 8.

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The QStat® Cartridge is a multi-channel cartridge that provides semi-quantitative indications of the coagulation and clot lysis state of a 3.2% citrated venous whole blood sample using the Quantra® Hemostasis Analyzer. The QStat Cartridge includes tests to assess coagulation via the intrinsic pathways and includes a test with tranexamic acid to evaluate clot lysis characteristics.

The QStat Cartridge is intended for in vitro diagnostic use by trained professionals at the point-of-care and in clinical laboratories to evaluate the viscoelastic properties of whole blood by means of the following functional parameters: Clot Time (CT), Clot Stiffness (CS), Fibrinogen Contribution to Clot Stiffness (FCS), Platelet Contribution to Clot Stiffness (PCS), and Clot Stability to Lysis (CSL).

The QStat Cartridge is indicated for the evaluation of blood coagulation and clot lysis in patients age 18 years and older to assess possible hypocoagulable conditions in trauma and liver transplantation procedures.

Results obtained with the OStat Cartridge should not be the sole basis for patient diagnosis.

For prescription use only.

The QStat Cartridge is a single-use, multi-channel (n=4) disposable plastic cartridge used with the Quantra Hemostasis Analyzer to assess a patient's coagulation and clot lysis (possible hypocoagulable and hypercoagulable conditions) in a hospital setting (point of care or laboratory) during trauma and liver transplantation procedures. The QStat Cartridge consists of four independent channels that can be tested simultaneously with Sonic Estimation of Elasticity via Resonance (SEER) Sonorheometry.

Each QStat Cartridge is pre-filled with reagents individually sealed in an airtight pouch. After a QStat Cartridge is removed from its primary packaging, it is inserted into the instrument dock. A venous whole blood sample, collected in a 3.2% sodium citrate anticoagulant blood collection tube (minimum volume 2.7 mL), is attached directly to the cartridge and the test is initiated using the touch screen interface on the Quantra Hemostasis Analyzer. The cartridge is the only component of the Quantra system that is in direct contact with blood. The fluidic system within the instrument draws the sample into the cartridge where it is warmed to 37℃, aliquoted, introduced and mixed with the lyophilized reagents, and analyzed. When the test is complete, the cartridge is released from the dock to be disposed of in an appropriate biosafety sharps container.

Each channel of the cartridge contains prefilled lyophilized reagents in the form of beads that enable differential testing without the need for any reagent preparation or pipetting before testing. The assay provides the following information for each patient sample: Clot Time (CT), Clot Stiffness (CS), Fibrinogen Contribution to Clot Stiffness (FCS), Platelet Contribution to Clot Stiffness (PCS) and Clot Stability to Lysis (CSL).

Here's an analysis of the provided text, extracting the requested information about acceptance criteria and the study proving device performance for the QStat® Cartridge:

Acceptance Criteria and Device Performance for QStat® Cartridge

1. Table of Acceptance Criteria and Reported Device Performance

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

• Clinical Performance Study (Method Comparison):
  • Sample Size: 289 adult subjects.
  • Data Provenance: Multi-center prospective observational study conducted at thirteen clinical sites in the US.
  • Sample Types: Involved blood samples from subjects undergoing liver transplant surgery, experiencing major trauma, and 5 normal subjects from whom contrived samples were prepared (6.7% of total samples were contrived by spiking blood from normal volunteers).
• Precision/Reproducibility Studies:
  • Single Site: QSL1 (N=80), QSL2 (N=80) for each parameter.
  • Multi-Site: 60 data points per parameter per sample type (unspiked, tPA spiked to CSL threshold, tPA spiked below CSL threshold) across all sites.
  • Whole Blood Repeatability: Varied per study, but generally involved multiple native and contrived samples (total of 16 sample types) and 12 results obtained from each sample type for variance analysis.
  • Data Provenance: Internal HemoSonics studies and external clinical sites within the US.
• Interference Study: "A total of n=13 native and contrived whole blood samples were evaluated for sample stability". Specific sample sizes for each interferent in screening and dose-response studies are not explicitly stated but are described as "n" or "multiple levels", "one or two levels", etc. The study utilized normal whole blood and hypocoagulable whole blood.
• Reference Range Study:
  • Sample Size: 155 healthy men and women volunteers (≥18 years of age).
  • Data Provenance: Multi-center, prospective, observational study across four (4) external sites in the United States.
• Reader Study:
  • Sample Size: 10 readers.
  • Data Provenance: Conducted with potential users who regularly assess blood coagulation status in critical care settings.

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

The document does not explicitly state the number of experts used to establish a ground truth in the traditional sense (e.g., for image labeling). Instead, the "ground truth" or reference for comparison in the method comparison study was the results from the predicate device, ROTEM Delta Thromboelastometry System, which is itself a commercially available and cleared device for similar measurements.

For the Reader Study, the "ground truth" was the correct interpretation of the QStat results displays as determined by the device's design and intended use, rather than an expert panel judging unknown cases.

4. Adjudication Method for the Test Set

Not applicable in the typical sense of expert adjudication of a test set, as the comparison was primarily against a predicate device (ROTEM delta) or against pre-defined control values and reference ranges.

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 MRMC comparative effectiveness study was performed or described in the provided text for comparing AI assistance to human readers. The Reader Study mentioned (Section P.1) was a usability study to assess interpretation of the device's results displays by potential users, not a comparative effectiveness study of AI impact on reader performance.

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

Yes, the primary performance studies listed under "Analytical Performance" (Precision/Reproducibility, Linearity, Stability, Detection Limit, Analytical Specificity) and "Comparison Studies" (Method Comparison with predicate device, Reference Range) all represent standalone performance of the QStat® Cartridge and Quantra Hemostasis Analyzer system without human intervention in the result generation process itself. The system provides semi-quantitative measurements directly.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

• Method Comparison Study: The predicate device (ROTEM delta) served as the comparative "truth" for evaluating linearity and clinical agreement of the QStat parameters. This is a common approach for establishing substantial equivalence for new diagnostic devices.
• Precision/Reproducibility Studies: Pre-defined control materials (QSL1, QSL2) and contrived samples (spiked with tPA, fibrinogen, DOACs) with expected values/characteristics served as the reference.
• Interference Studies: Pre-determined concentrations of known interferents and their expected effects/non-effects.
• Reference Range Study: Healthy volunteers (n=155) were used to establish normal reference intervals.

8. The Sample Size for the Training Set

The document does not provide details of a specific "training set" size. As this is a diagnostic device that measures viscoelastic properties rather than an AI/ML algorithm that predicts outcomes, the concept of a separate "training set" for model development, distinct from analytical and clinical validation data, is not directly applicable or explicitly detailed in this 510(k) summary. The data presented primarily relates to the analytical and clinical validation of the device.

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

As explained under point 8, the document does not discuss a specific "training set" in the context of an AI/ML model. The QStat Cartridge uses "Sonic Estimation of Elasticity via Resonance (SEER) Sonorheometry" to quantify shear modulus, which is a physics-based measurement, not a machine learning prediction. Therefore, the establishment of "ground truth for the training set" is not relevant for this type of device according to the provided text.

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