(349 days)
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
| Parameter / Study Type | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Precision/Reproducibility | ||
| Single Site Precision (QSL1) | Within-laboratory precision (total) CV% for CT, CS, FCS parameters ≤ 9.5% | CT: 3.5% CV, CS: 5.6% CV, FCS: 9.5% CV |
| Single Site Precision (QSL2) | Within-laboratory precision (total) CV% for CT, CS, FCS parameters ≤ 9.3% | CT: 6.1% CV, CS: 9.3% CV, FCS: 9.0% CV |
| Single Site Precision (Fibrinolysis-positive controls) | Total %CV for CT, CS, FCS below 5.8%. | |
| Total %CV for CSL below 7.1% OR total SD for CSL below 10.2% | CT, CS, FCS: ≤ 5.8% CV | |
| CSL: 7.1% CV and 10.2% SD | ||
| Multi-Site Reproducibility (CSL, Normal Sample) | Total imprecision of CSL parameter 95% of questions pertaining to each display answered correctly | >95% correctly answered for all five QStat parameters |
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.
§ 864.5430 Coagulation system for the measurement of whole blood viscoelastic properties in perioperative patients.
(a)
Identification. A coagulation system for the measurement of whole blood viscoelastic properties in perioperative patients is an in vitro diagnostic device used to evaluate blood coagulation, fibrinolysis, or both, in perioperative patients, as an aid in the assessment of coagulopathies when used in conjunction with clinical signs and symptoms and other clinical and laboratory findings.(b)
Classification. Class II (special controls). The special controls for this device are:(1) Design verification and validation must include detailed documentation of, and results from, the following:
(i) A study assessing precision using protocols determined to be acceptable by FDA, to cover the measurement range for each reported parameter (test output). Testing must include native specimens with coagulation profiles representative of the intended use population. In order to cover the measuring range, testing may include a limited number of contrived specimens, not to exceed 10 to 20 percent, or as otherwise deemed appropriate by FDA. The contrived specimens must be prepared to resemble clinical specimens. This testing must evaluate repeatability and reproducibility and provide assessments of within-run, within-day, between-run, between-day, between-reagent lot, between-instrument, between-site, and between-operator precision, as applicable to the system;
(ii) Studies that demonstrate the performance of each parameter (test output) throughout the claimed measurement range, to include linearity studies or dose-response studies, as applicable to the parameter (test output);
(iii) Potential interferent study that includes evaluation of hemolyzed and lipemic samples as potential interferents; exogenous and endogenous interferents associated with each patient population intended for use with the device, and which might be expected to affect assay performance, must be evaluated; and potential interferents that are specific for, or related to, the technology or methodology of the device. Evaluation of all potential interferents must be performed using a protocol determined to be acceptable to the FDA (
e.g., an FDA-recognized standard) and include both normal and abnormal specimens covering coagulation profiles representative of the intended use population;(iv) A study that evaluates specimen stability under the intended conditions for specimen collection, handling, and storage, using samples that cover the coagulation profiles representative of the intended use population, and using protocols determined to be acceptable by FDA;
(v) A multisite clinical study, determined to be acceptable by FDA, demonstrating performance, relative to clinically relevant and clinically validated laboratory test(s) for each parameter (test output). Further, the study must meet all of the following criteria:
(A) The study must be performed in the intended use population and include representation from all patient populations for whom the device is intended to be used. Potential endogenous and exogenous interferents for each target patient population must be evaluated or known prior to the study;
(B) The study must be conducted at a minimum of three external sites representative of the intended use setting by the intended operators;
(C) Test samples must be collected at time intervals relevant to the device's use in the intended use population;
(D) Clinical specimens, which cover coagulation profiles representative of the intended use population, must be evaluated at each of the three clinical sites in the study;
(E) Analysis of the concordance of clinical interpretation of patient coagulation status made from individual test parameter (test output) results as compared to clinical interpretation of coagulation status from a clinically relevant laboratory test or tests (
e.g., a comparative viscoelastic device or standard laboratory tests) must be conducted; and(F) Expected (reference) values for each parameter (test output) must be demonstrated by testing a statistically appropriate number of samples from apparently healthy normal individuals;
(vi) For a device with a user interface that has information that needs to be interpreted by the user in correctly using the device to achieve the intended test results or a device that does not provide a final output that is a comprehensive interpretation of all parameter (test output) results, a study evaluating the ability of device users to correctly interpret results;
(vii) For any device indicated to guide blood product use, a clinical outcome study determined to be acceptable by FDA that specifically validates the device's indicated use in guiding blood product use; and
(viii) For any device indicated to guide use of medication, a clinical outcome study determined to be acceptable by FDA that specifically validates the device's indicated use in guiding use of medication.
(2) The labeling required under § 809.10(b) of this chapter must include the following:
(i) A summary of results from the study required by paragraph (b)(1)(i) of this section, including repeatability, reproducibility, and assessments of within-run, within-day, between-run, between-day, between-reagent lot, between-instrument, between-site, and between-operator precision, as applicable to the system.
(ii) The claimed measurement range of each parameter (test output), as supported by demonstrated performance of the parameter (test output) throughout the claimed measurement range, including studies required by paragraphs (b)(1)(i) through (iii) and (v) of this section, and, if applicable, paragraphs (b)(1)(vii) and (viii) of this section.
(iii) Identification of known interferents, including all endogenous, exogenous, technology-specific, and patient population-specific interferents, specific to each parameter (test output). The information must include the concentration(s) or level(s) at which interference was found to occur and the concentration range or levels at which interference was not found to occur.
(iv) Information regarding the multisite clinical study required by paragraph (b)(1)(v) of this section, including:
(A) Each patient population evaluated;
(B) Each intended use setting and the operators;
(C) A summary of the results, including the concordance analysis to clinically relevant laboratory test(s); and
(D) Demonstrated expected (reference) values for each parameter (test output).
(3) The labeling required under § 809.10 of this chapter must include the following:
(i) A limiting statement that the result(s) from the device is(are) not intended to be used as the sole basis for a patient diagnosis.
(ii) Unless appropriate clinical outcome studies are done in accordance with paragraph (b)(1)(vii) of this section that specifically validate an indication for the device's use in guiding blood product use, a limiting statement that the device has not been evaluated to guide blood product use.
(iii) Unless appropriate clinical outcome studies are done in accordance with paragraph (b)(1)(viii) of this section that specifically validate an indication for the device's use in guiding use of medication, a limiting statement that the device has not been evaluated to guide use of medication.