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The Quantra QPlus System is intended for in vitro diagnostic use.

The system is intended to be used 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 Time with Heparinase (CTH), Clot Stiffness (CS), Fibrinogen Contribution to Clot Stiffness (FCS), Platelet Contribution to Clot Stiffness (PCS), and Clot Time Ratio (CTR).

The Quantra QPlus System is indicated for the evaluation of blood coagulation in perioperative patients age 18 years and older to assess possible hypocoagulable and hypercoagulable conditions in cardiovascular or major orthopedic surgeries before, during, and following the procedure.

Results obtained with the Quantra QPlus System should not be the sole basis for patient diagnosis.

For prescription use only.

The Quantra OPlus System is an in vitro diagnostic device designed to assess a patient's coagulation status by measuring the shear modulus of a blood sample during clot formation in perioperative settings in the point of care (POC) or clinical laboratory settings. The system consists of the Quantra Hemostasis Analyzer (instrument), QPlus Cartridge (singleuse disposable cartridge), Quantra Controls Level 2 (external quality control materials), and the Quantra Cleaning Cartridge.

The Quantra Hemostasis Analyzer is a fully integrated and automated in vitro diagnostic device designed to assess a patient's coagulation status by measuring the viscoelastic properties of a blood sample during clot formation. The analyzer consists of a base instrument with a software component. The instrument and the software are a closed system, using only Quantra assay cartridges.

The QPlus Cartridge is a single-use four-channel plastic cartridge which has a sample port on one end to draw the blood sample into the cartridge without requiring any sample pipetting. Lyophilized reagents are embedded into the four channels within the cartridge. The four channels enable four independent reactions/tests to be run simultaneously.

The cartridge comes sealed in a foil pouch. After a OPlus 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 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 analyzer displays the test results in three different views: dial display screen, stiffness curves, and trend data. The dial display screen is the primary viewing screen and has a dial for each of the six output parameters. Each dial shows the reference range, assay measurement range, parameter abbreviation, and the numerical result for the corresponding parameter. The stiffness curves are a graphical display of shear modulus measurements over time that enable the user to view the development of clot stiffness over time. The trend data display provides numeric results of tests run during the past 48 hours for a specific patient. In the trend data view, multiple samples from the same patient are displayed.

The device outputs four directly measured parameters (Clot Time, Clot Time with Heparinase, Clot Stiffness, and Fibrinogen Contribution to Clot Stiffness) as well as two calculated parameters (Clot Time Ratio and Platelet Contribution to Clot Stiffness).

Acceptance Criteria and Device Performance for The Quantra QPlus System

The Quantra QPlus System's performance was evaluated through various studies to demonstrate its analytical and clinical capabilities. The acceptance criteria largely stemmed from the regulatory requirements outlined in 21 CFR §864.5430(b)(1).

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are derived from the special controls specified in 21 CFR §864.5430(b)(1). The reported device performance is summarized from the analytical and clinical studies described in the document.

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

• Clinical Performance Study:

  • Total Subjects: 277 eligible subjects (initially 302 consented, 25 did not complete).
  • Patient Categories:
    • 264 patients undergoing cardiac, vascular, or orthopedic surgery
    • 7 patients presented with acute bleeding or suspected hypercoagulation post-cardiac surgery
    • 13 patients with abnormal coagulation profiles
    • 18 normal individuals whose blood was artificially manipulated (contrived) to mimic abnormal coagulation profiles (used to supplement clinical data).
  • Data Provenance: Multi-center, prospective observational study conducted in the United States at four clinical sites (University of Virginia School of Medicine, Duke University Medical Center, Medical University of South Carolina, and University of Maryland School of Medicine).

• Reference Range Study:

  • Total Subjects: 129 eligible subjects (initially 158 healthy male and female volunteers >= 18 years old were enrolled).
  • Data Provenance: Multi-center, prospective, observational study across three external sites in the United States.

• Precision Studies (Whole Blood Repeatability):

  • Whole Blood Specimens: Included normal, abnormal, and contrived samples to cover reportable ranges. Specific 'n' values range from 3 to 20 for different parameters and ranges in the detailed tables.
  • Data Provenance: Conducted at one internal site.

• Interference Study:

  • Whole Blood Samples: Spiked normal and hypocoagulable blood (heparin-treated, abciximab-treated, fibrinogen-depleted plasma).
  • Data Provenance: Not explicitly stated, but typically conducted in a laboratory setting.

3. Number of Experts and Qualifications for Ground Truth

The document does not explicitly state the number of experts used to establish ground truth for the test set in the same way one might describe a panel of radiologists reviewing images. Instead, the ground truth for the clinical performance study relied on:

• Standard Laboratory Tests (SLTs): These are FDA-cleared and widely accepted methods (e.g., aPTT, ACT, INR, Clauss fibrinogen, platelet count).
• ROTEM delta Thromboelastometry System: An FDA-cleared viscoelastic device (K101533, K083842).

The "Clinical Composite Indices (CCIs)" were developed "based on in-depth review of the clinical literature, clinical guidelines and consideration from multiple physicians." While "multiple physicians" were involved in developing these indices, their specific number and qualifications (e.g., years of experience, specialty) are not detailed for establishing the ground truth of individual cases within the test set.

4. Adjudication Method

No explicit adjudication method (e.g., 2+1, 3+1) is described for resolving disagreements in ground truth for the clinical test set. The ground truth was established by:

• Clinically relevant and validated standard laboratory tests (SLTs): These tests inherently have established methodologies and result interpretations.
• The ROTEM delta Thromboelastometry System: Also an established device with its own interpretation criteria.
• Clinical Composite Indices (CCIs): Criteria for these indices were defined based on literature and physician input, providing objective classification categories ("Low," "Normal/Subclinical," "High").

The comparison was then made between the Quantra QPlus System's classification and the classification derived from these objective comparators. Therefore, rather than a subjective adjudication process, this relied on agreement with established, objective laboratory and device results.

5. Multi Reader Multi Case (MRMC) Comparative Effectiveness Study

No explicit MRMC comparative effectiveness study, evaluating how much human readers improve with AI vs. without AI assistance, was conducted or described in this document. The "Reader Study" (Section O) focused solely on the ability of potential Quantra users to correctly interpret results displayed on the Quantra Hemostasis Analyzer's dial display screen, rather than a comparison of diagnostic accuracy with and without AI assistance to human interpretation.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance)

Yes, the primary performance evaluation of the Quantra QPlus System (which includes the analyzer and its embedded software/algorithm) focused on its standalone performance. The analytical performance studies (precision, linearity, interference, stability) and the clinical concordance studies (against SLTs and ROTEM) all evaluated the device's ability to accurately measure and classify coagulation parameters directly, without human interpretation influencing the measurement itself. The "Reader Study" evaluated the user's ability to interpret the device's output, confirming appropriate human-device interaction, but the core measurement and classification performance is standalone.

7. Type of Ground Truth Used

The ground truth used for evaluating the clinical performance of the Quantra QPlus System was a combination of:

• Standard Laboratory Tests (SLTs): These included aPTT, ACT, INR, Clauss fibrinogen, and platelet count. These are widely accepted and routinely used in clinical practice.
• A Comparative Viscoelastic Device (ROTEM delta): This is an FDA-cleared device that provides similar viscoelastic measurements.
• Clinical Composite Indices (CCIs): These were derived from the SLT data and the status of heparin use, developed based on clinical literature, guidelines, and physician input. These effectively codified expert consensus into objective criteria for classifying coagulation states.
• Pathology/Outcomes Data: Not directly mentioned as primary ground truth, but the relevance of coagulation assessment for perioperative patients is linked to patient outcomes (e.g., blood product usage, bleeding/thrombosis risk).

8. Sample Size for the Training Set

The document does not specify a separate "training set" or its sample size. This is typical for a De Novo submission for a diagnostic device like the Quantra QPlus System, which is an in vitro diagnostic (IVD) device. The device's algorithms for calculating parameters (CT, CTH, CS, FCS, PCS, CTR) are based on the physics of SEER Sonorheometry and established coagulation principles, rather than being "trained" on a large dataset of clinical images or physiological waveforms in the way a deep learning AI model would be.

The "functional response studies" (e.g., heparin dose-response, platelet/fibrinogen levels) could be seen as part of the developmental work that informed the algorithm's design and parameter calculation methods, ensuring they reflect known biological responses. These studies involve spiking samples from a smaller number of donors (e.g., 5 normal donors for heparin, 4 donors for platelet count, etc.).

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

As noted above, there isn't a traditional "training set" with ground truth established in the AI/machine learning sense. The device's underlying principles are based on the physics of mechanical properties of clots and their progression. The "ground truth" for developing and validating the functional calculations within the device would have involved:

• Known concentrations/manipulations: For instance, in dose-response studies, blood samples were spiked with known concentrations of heparin or platelet inhibitors, or adjusted to known platelet/fibrinogen levels. The expected outcome (e.g., linear increase in CT with heparin, decrease in CS/PCS with platelet inhibition) serves as the "ground truth" for the algorithm's ability to reflect these changes.
• Reference methods: Fibrinogen levels, for example, were confirmed using the Clauss fibrinogen assay, a standard reference method.

This approach ensures the device accurately measures the intended physical properties and reflects real-world physiological changes in a quantifiable manner.

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The EXTEM assay is a semi-quantitative in vitro diagnostic assay on the ROTEM® delta Thromboelastometry System to monitor the coagulation process via the extrinsic pathway in citrated whole blood specimens. Clotting characteristics are described by the functional parameters Clotting Time (CT), Speed of Clot Formation (CFT and alpha angle), Clot Firmness (A20/MCF) and Clot Lysis (LOT, ML, LI(x)). Speed of clot formation time (CFT and alpha) is complementary parameter and should be used only in conjunction with the main parameters Clotting time (CT) and Clot Firmness (A20/MCF). The indication for ROTEM® delta use is in adult patients where an evaluation of their blood coagulation properties is desired. Coagulation evaluations with the ROTEM® delta system are commonly used to assess clinical conditions in organ transplantation, cardiovascular surgery, cardiology procedures and trauma to assess post-operative hemorrhage and / or thrombosis.

The FIBTEM assay is a semi-quantitative in vitro diagnostic assay on the ROTEM® delta Thromboelastometry System to monitor the clot firmness of a citrated whole blood specimens after blocking platelet contribution to the clot firmness The fib-TEM® reagent is always used in conjunction with ex-TEM® reagent. Clotting characteristics are described by the functional parameter Clot Firmness (A20/MCF). The indication for ROTEM® delta use is in adult patients where an evaluation of their blood coagulation properties is desired. Coagulation evaluations with the ROTEM® delta system are commonly used to assess clinical conditions in organ transplantation, cardiovascular surgery, cardiology procedures and trauma to assess post-operative hemorrhage and / or thrombosis.

The APTEM assay is a semi-quantitative in vitro diagnostic assay on the ROTEM® delta Thromboelastometry System to monitor the clot firmness of a citrated whole blood specimens after blocking hyperfibrinolysis by aprotinin. The ap-TEM® reagent is always used in conjunction with ex-TEM® reagent. Clotting characteristics are described by the functional parameters Clotting Time (CT), Speed of Clot Formation (CFT and alpha angle), Clot Firmness (A20/MCF) and Clot Lysis (LOT, ML, LI(x)). Speed of clot formation time (CFT and alpha) is complementary parameter and should be used only in conjunction with the main parameters Clotting time (CT) and Clot Firmness (A20/MCF). The indication for ROTEM® delta use is in adult patients where an evaluation of their blood coagulation properties is desired. Coagulation evaluations with the ROTEM® delta system are commonly used to assess clinical conditions in organ transplantation, cardiovascular surgery, cardiology procedures and trauma to assess post-operative hemorrhage and / or thrombosis.

The ROTEM® delta Thromboelastometry System consists of a fourcolumn instrument (with integrated computer module, computer controlled electronic pipette, software), system reagents (in-TEM®, hep-TEM®, star-TEM®, ex-TEM®, fib-TEM® and ap-TEM®, quality controls (ROTROL N, ROTROL P) and measurement cells (Cup and Pin pro). The blood sample is filled into a cylindrical cup. A pin oscillates permanently while it is immersed in the blood holding cup. The motion of the pin is detected by an optical detection system. Data are processed and analyzed by a computer with special software. If no clotting takes place, the movement of the pin is not obstructed. When a clot forms and attaches itself to the pin and cup surfaces, the movement is obstructed. As the clot becomes firmer, the rotational movement of the pin is reduced. The rotational movement of the pin is converted into amplitude with the following definitions applying to the thromboelastogram (TEM): Amplitude of 0 mm means unobstructed oscillation, while amplitude of 100 mm can be regarded as infinite firmness and blocking of the pin by the clot. The TEM amplitude is a measure of the clot firmness.

Here's a breakdown of the acceptance criteria and study information for the ROTEM® delta Thromboelastometry System, based on the provided text:

Acceptance Criteria and Device Performance

The acceptance criteria are primarily focused on the precision of the ROTEM® delta system's assays (EXTEM, FIBTEM, APTEM) and their comparability to the predicate device (TEG® 5000).

1. Table of Acceptance Criteria and Reported Device Performance

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

• Sample Size:
  • EXTEM Method Comparison: CT vs. R (n=100), CFT vs. K (n=91), α vs. Angle (n=100), MCF vs. MA (n=93).
  • APTEM Method Comparison: CT vs. R (n=84), CFT vs. K (n=73), α vs. Angle (n=82), MCF vs. MA (n=79).
  • FIBTEM Method Comparison: MCF vs. MA (n=88).
  • Precision Studies: Conducted with healthy donor blood and ROTROL N control. Specific sample numbers are not provided beyond "5 runs on each of the 4 channels of one instrument" and "5 operators run ROTROL N in duplicates."
  • Reference Ranges: Estimated using the CSLI C28-A2 guideline on three clinical US reference sample groups, with results consistent with earlier European studies.
• Data Provenance:
  • Method Comparison: Patient samples from 3 US centers. These patients were during surgery and post-surgery in the intensive care unit (ICU). Contrived samples were added to broaden the range of comparison.
  • Reference Ranges: US and European reference sample groups.
  • Retrospective/Prospective: Not explicitly stated, but the mention of "patient samples during surgery and post surgery at the intensive care unit (ICU)" and "contrived samples were added" for the method comparison, along with "healthy donor blood" for precision, suggests a mix of prospective collections and prepared samples.

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

The document does not explicitly state the number of experts or their qualifications for establishing ground truth. The "ground truth" in this context is the measurement provided by the predicate device, TEG® 5000, which is a legally marketed device. The study seeks to establish substantial equivalence to this predicate.

4. Adjudication Method for the Test Set

Not applicable. The study is a direct comparison of measurements between the investigational device (ROTEM® delta) and the predicate device (TEG® 5000), not an interpretation that would require an adjudication method.

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

No, an MRMC comparative effectiveness study was not done. This study focuses on the analytical performance (precision and method comparison) of the device itself against a predicate, not on how human readers' performance changes with or without AI assistance.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, the studies presented are standalone performance studies of the ROTEM® delta system and its reagents. The device generates quantitative functional parameters (CT, CFT, Alpha, A20/MCF), and the study evaluates the accuracy and precision of these measurements, as well as their correlation to the predicate device. There is no human-in-the-loop component being evaluated for this 510(k) submission.

7. The Type of Ground Truth Used

The primary "ground truth" used for method comparison is the measurements obtained from the predicate device, the TEG® 5000 Thrombelastograph.

For precision studies, the ground truth involves the expected consistency of measurements on controlled samples (healthy donor blood, internal controls like ROTROL N).

For reference ranges, the ground truth is established through analysis of measurements from "clinical US reference sample groups" and consistency with "earlier studies on European reference sample groups."

8. The Sample Size for the Training Set

The document does not mention a "training set" in the context of device development or any machine learning algorithms. The study focuses on the validation of the device's analytical performance.

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

Not applicable, as no training set for a machine learning model is mentioned or implied in the provided text. The device's measurement principle is based on physical oscillation detection and established thromboelastometry principles, rather than a learned algorithm needing a separate training phase.

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