(111 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 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 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 and hypercoagulable conditions in trauma, liver transplantation, and peripartum obstetric 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 analyzer displays the test results (n=5) in three different views: dial display screen, stiffness curves data, and trend screen. The dial display screen is the primary viewing screen and has a dial for each of the five 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 trends screen displays results from a patient for up to six time points.
There are two levels of external QStat Controls (QSL1 and QSL2) that are supplied separately (required but not provided materials) for testing on the Quantra System when changing cartridge lots, changing control lots, or after significant changes are made to the Quantra instrument (e.g., software update).
The FDA 510(k) clearance letter for the Quantra QStat Cartridge describes its intended use for evaluating blood coagulation and clot lysis, specifically extending its indication to peripartum obstetric patients. The submission refers to non-clinical and clinical tests to demonstrate the device meets acceptance criteria.
Here's a breakdown of the requested information based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state quantitative acceptance criteria in a table format. However, it describes acceptable performance in relation to interference and clinical agreement.
| Acceptance Criteria (Implied from Study Description) | Reported Device Performance |
|---|---|
| No significant interference from common obstetric medications (hemabate, methergine, misoprostol, oxytocin) | The highest concentration of each substance tested showed no significant interference in whole blood samples collected in 3.2% sodium citrate anticoagulant collection tubes. |
| Clinical agreement between QStat CSL and ROTEM delta EXTEM ML for identifying fibrinolytic samples. | Overall agreement of patient sample assignments into lysis-positive and lysis-negative based on data for QStat CSL and ROTEM delta EXTEM ML was 92%. |
| Correlation between QStat FCS and fibrinogen levels. | Passing-Bablok regression analysis showed good agreement between the methods (slope = 1, r = 0.815), albeit with a constant bias. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size (Clinical Study): 322 subjects
- Data Provenance: Prospective observational study, conducted across seven clinical sites in the US. The study involved parturients (women in labor) aged 18 years or older with concerns for coagulopathy.
- Sample Size (Interference Study): Not explicitly stated with a specific number for the test set, but it mentioned "normal and hypercoagulable whole blood specimens" and that the "number of replicates at each level of a screening study was targeted to provide a 95% confidence interval (2-sided), per CLSI EP07-A2 Guideline."
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not specify the number or qualifications of experts used to establish ground truth for the clinical test set. Instead, ground truth for some parameters appears to be established by comparison to other legally marketed and established devices (ROTEM delta, TEG 5000) and conventional coagulation testing (aPTT, PT/INR, fibrinogen level, platelet count).
4. Adjudication Method for the Test Set
The document does not describe an adjudication method involving experts for establishing ground truth. The comparison is made against existing, accepted methods and devices.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
There is no mention of a multi-reader multi-case (MRMC) comparative effectiveness study, nor any effect size regarding human reader improvement with or without AI assistance. This device is an in vitro diagnostic (IVD) device that measures coagulation parameters, not an AI-assisted diagnostic imaging or interpretation tool.
6. Standalone (Algorithm Only) Performance Study
Yes, the studies described are standalone performance studies. The clinical and analytical specificity studies evaluate the performance of the QStat Cartridge and Quantra Hemostasis Analyzer directly, not in conjunction with human interpretation for the primary measurement. The comparisons are to other standalone diagnostic methods (ROTEM delta, TEG 5000, conventional coagulation tests).
7. Type of Ground Truth Used
The ground truth used for the clinical performance evaluation was based on:
- Comparison to legally marketed viscoelastic testing devices: ROTEM delta or TEG 5000.
- Comparison to conventional coagulation testing: aPTT, PT/INR, fibrinogen level, platelet count.
- The "concern for coagulopathy" as a trigger for testing suggests clinical suspicion as an initial selection criterion, with the aforementioned tests serving as the gold/reference standard for comparison.
8. Sample Size for the Training Set
The document does not provide information about a separate training set or its sample size. The studies described appear to be focused on performance validation.
9. How the Ground Truth for the Training Set Was Established
As no training set is mentioned, there is no information on how its ground truth was established.
§ 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.