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The TEG 6s Hemostasis System consists of the TEG 6s Hemostasis Analyzer and the Citrated: K, KH, RTH, FFH assay cartridge. The TEG 6s Hemostasis System is intended for in vitro diagnostic use with adult patients where an evaluation of their blood hemostasis properties is desired. The TEG 6s Hemostasis System records the kinetic changes in a sample of 3.2% citrated whole blood as the sample clots and provides semi-quantitative results. The TEG 6s Hemostasis System can be used in the laboratory or at the point-of-care.

The Citrated: K, KH, RTH, FFH assay cartridge is intended to be used in patients where heparin/heparinoids may be present and who are at an increased risk of coagulopathy. Hemostasis evaluations are indicated to assess clinical conditions in cardiovascular surgery, cardiovascular procedures (e.g. minimally invasive valve replacement or repairs) and liver transplantation to assess hemorrhage or thrombosis conditions before, during and following the procedure.

The Citrated: K, KH, RTH, FFH assay cartridge contains four independent assays (CK, CKH, CRTH and CFFH) and the system output consists of a table of numerical values for parameters R, MA, and LY30.

The CK assay monitors the hemostasis process via the intrinsic pathway in 3.2% citrated whole blood specimens on the TEG 6s Hemostasis System. Clotting characteristics are described by the functional parameters R (clotting time) and MA (maximum clot strength).

The CKH assay monitors the effects of heparin in 3.2% citrated whole blood specimens on the TEG 6s Hemostasis System. CKH is used in conjunction with CK, and heparin influence is determined by comparing Clotting Times (R) between the two tests. LY30 describes fibrinolysis 30 minutes after reaching maximum clot strength.

The CRTH assay monitors the hemostasis process after stimulation of both the intrinsic and extrinsic pathways in 3.2% citrated whole blood specimens on the TEG 6s Hemostasis System, neutralizing the effect of heparin in the sample. Clotting characteristics are described by the functional parameter MA (maximum clot strength with contributions of both platelets and fibrin).

The CFFH assay monitors hemostasis of 3.2% citrated whole blood specimens in the TEG 6s Hemostasis System after blocking platelet contributions to clot strength, neutralizing the effect of heparin in the sample. Clotting characteristics are described by the functional parameter MA (fibrinogen contribution to maximum clot strength).

Results from the TEG 6s analysis should not be the sole basis for a patient diagnosis, but should be evaluated together with the patient's medical history, the clinical picture and, if necessary, further hemostasis tests.

For professional use only.

The TEG® 6s Hemostasis System (TEG® hemostasis analyzer and TEG® 6s assay cartridges) is intended for in vitro diagnostic use to provide semi-quantitative indications of a blood sample's ability to form and maintain a clot. The TEG® 6s Hemostasis System records the kinetic changes in a sample of whole blood as the sample clots, retracts and/or lyses. The system output consists of a table of numerical values and graphs resulting from the hemostasis process over time. This information can be used by clinicians to aid in determining if a clotting dysfunction or coagulopathy is present.

To perform a test, a disposable TEG® 6s assay cartridge is inserted into the TEG® 6s hemostasis analyzer. The instrument reads the bar code on the cartridge and identifies the type of cartridge for operator confirmation. Blood (collected in a 3.2% sodium citrate tube) or Quality Control (QC) material is added to the entry port on the cartridge and drawn into the cartridge under the TEG® 6s hemostasis analyzer control. The amount of the sample drawn into the cartridge is determined by the pre-set volume of the blood chambers in the cartridge. Once in the cartridge, the sample is metered into as many as 4 separate analysis channels, depending upon the assays being performed. Reconstitution of reagents dried within the cartridge is accomplished by moving the sample back and forth through reagent chambers, under the control of microfluidic valves and bellows (pumps) within the cartridge. After each sample has been mixed with reagent, it is delivered to a test cell where it is monitored for viscoelastic changes due to coagulation. Excess sample material is moved under microfluidic control into an enclosed waste chamber within the cartridge.

The TEG® 6s technology is based on a disposable cartridge containing up to 4 independent measurement cells. Each cell consists of a short vertically-oriented injection molded tube (ring). Detection of clotting in the TEG® 6s Hemostasis System is performed optically. A piezoelectric actuator vibrates the measurement cell(s) through a motion profile composed of summed sinusoids at different frequencies. The movement of the measurement cells will induce motion in the sample meniscus, which will be detected by a photodiode. The resulting motion of the meniscus is monitored optically and analyzed by the instrument to calculate the resonant frequency and modulus of elasticity (stiffness) of the sample. By performing a Fast Fourier Transform (FFT) on meniscus motion data, the resonant frequencies can be determined. The analyzer monitors the harmonic motion of a hanging drop of blood in response to external vibration. As the sample transitions from a liquid state to a gel-like state during clotting, the modulus of elasticity (stiffness) and therefore resonant frequency increase. The TEG® 6s hemostasis analyzer measures these variations in resonant frequency during clotting and lysis.

Resonance is the tendency of a material or structure to oscillate with greater amplitude at some frequencies than others. The exact frequencies at which resonance occurs will depend on the stiffness and mass of the sample. Stiffness, in turn, is a function of a material's modulus of elasticity and the boundary conditions to which the material is exposed, such as the geometry and materials of a test cell. By holding these boundary conditions and sample mass constant from sample to sample, the TEG® 6s Hemostasis System allows direct comparison of elasticity between samples. The output measurements are displayed in a table and on a graphical tracing that reflects the hemostasis profile of the clot formation.

In a typical test, blood that has been delivered to the measurement cell will not clot for several minutes. During this time the sample has no inherent stiffness except that provided by surface tension, and since this remains constant the measured resonant frequencies will not change.

Once clotting begins, however, the elastic modulus and thus the resonant frequencies increase rapidly. During fibrinolysis, the process is reversed, with elastic modulus and resonant frequencies decreasing. In tests where clotting does not occur, the resonant frequency of the sample will not change. During coagulation, however, a clot will bind to the ring contained in the cartridge and the resonant frequency will rise with increasing firmness of the clot. The TEG® 6s hemostasis analyzer collects meniscus motion data, tracks changing resonant frequencies and analyzes the frequency data to provide semi-quantitative parameters describing the clot.

The TEG® 6s Hemostasis System monitors the interaction of platelets within the fibrin mesh of the clot during clot formation and lysis, all in a whole-blood setting. The TEG® 6s Hemostasis System uses thromboelastography to provide continuous measurement of clot elasticity.

The provided text describes the acceptance criteria and study proving that the "Citrated: K, KH, RTH, FFH" assay cartridge for the TEG 6s Hemostasis System meets these criteria.

Here's a breakdown of the requested information:

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

• CK-R: 0.82 (CK-R: 0.90, CK-MA: 0.95, CKH-R: 0.82, CKH-LY30: 0.99, CRTH-MA: 0.97).
  Type 3 Parameter (CFFH-MA vs. Clauss Fibrinogen):
• Spearman correlation coefficient: 0.79 (95% CI: 0.757; 0.814). | Pass |
  | Electrical Safety & EMC | Compliance with IEC 61010-1, IEC 61010-2-010, IEC 61010-2-101 for safety; and IEC 60601-1-2, IEC/EN61326-1, IEC/EN61326-2-6 for EMC. | "The system complies with the IEC 61010-1, IEC 61010-2-010, IEC 61010-2-101, standards for safety and the IEC 60601-1-2, IEC/ EN61326-1, IEC/ EN61326-2-6, standards for EMC." | Pass |
  | Software Verification & Validation | Documentation as recommended by FDA guidance for "moderate" level of concern. | "Software verification and validation testing were conducted and documentation was provided as recommended by FDA's Guidance..." | Pass |

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

• Sample Sizes (Clinical Performance - Method Comparison):
  • CK-R: 617 samples
  • CK-MA: 539 samples
  • CKH-R: 829 samples
  • CKH-LY30: 828 samples
  • CRTH-MA: 870 samples
  • CFFH-MA: 883 samples
• Data Provenance:
  • Country of Origin: United States ("All studies were performed in the United States.")
  • Retrospective or Prospective: Prospective clinical trials (indicated by "patients undergoing liver transplantation, cardiovascular surgery, or cardiology procedures. Blood samples were drawn before, during, and after the procedures"). These samples were collected at eight clinical trial sites.

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 information is not provided in the document. The comparability study uses predicate devices (TEG 6s with Citrated Multichannel Cartridge and Clauss Fibrinogen) as comparators, not expert consensus on ground truth conditions.

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

This information is not provided in the document. The study uses comparison to predicate devices/methods rather than a ground truth established by an adjudication process.

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

• Was an MRMC study done? No.
• Effect size of human readers improvement with/without AI: Not applicable, as this is an in-vitro diagnostic device for blood hemostasis properties, not an AI-assisted diagnostic tool for human readers interpreting images or data.

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

Yes, the device operates in a standalone manner, providing semi-quantitative results for blood hemostasis properties. The clinical performance testing is a method comparison study, where the device's results are compared to those of predicate devices/established methods, without explicit human interpretation as part of the primary performance metric. The results are numerical values and graphs. The device's output is "not the sole basis for a patient diagnosis, but should be evaluated together with the patient's medical history, the clinical picture and, if necessary, further hemostasis tests," indicating that a human interprets the device's standalone results, rather than the human being part of the measurement process itself.

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

The ground truth for the clinical performance study (method comparison) was primarily based on:

• Comparison to legally marketed predicate devices (TEG 6s with the Citrated Multichannel Cartridge) for most parameters (CK-R, CK-MA, CKH-R, CKH-LY30, CRTH-MA using CKH-MA from the predicate as an equivalent channel).
• Comparison to Clauss Fibrinogen plasma concentration for CFFH-MA, as an established method for measuring fibrinogen contribution to clot formation.

8. The sample size for the training set

This information is not explicitly provided as a "training set" in the context of machine learning. However, reference ranges were established using 148-162 samples from "normal donors" (see section 14.A. Reference Ranges), and various precision studies involved hundreds of measurements using QC materials and normal/contrived whole blood samples. This constitutes data used for establishing operational parameters and validating performance characteristics, which is analogous to a training or development set for IVDs.

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

For the establishment of reference ranges, "Citrated whole blood from normal donors (representative of normal population distributions - age, gender, race) with no known coagulopathies and not taking any drugs that would potentially affect patient hemostasis was used." A non-parametric method for analysis was used to determine the reference range for each assay parameter. For precision studies, QC materials with known values and contrived blood samples simulating various hemostatic states (hypo-coagulable, hyper-coagulable, hyper-fibrinolytic) were used. The "ground truth" for these samples refers to their classification as normal or contrived states and the expected behavior based on the additives.

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