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The i-STAT TBI test is a panel of in vitro diagnostic immunoassays for the quantitative measurements of glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) in whole blood and a semi-quantitative interpretation of test results derived from these measurements, using the i-STAT Alinity instrument. The interpretation of test results is used, in conjunction with other clinical information, to aid in the evaluation of patients, 18 years of age or older, presenting with suspected mild traumatic brain injury (Glasgow Coma Scale score 13-15), which may include one of the following four clinical criteria: 1) any period of loss of consciousness, 2) any loss of memory for events immediately before and after the accident, 3) any alteration in mental state at the time of accident, and/or 4) focal neurological deficits, within 24 hours of injury, to assist in determining the need for a CT (computed tomography) scan of the head. A 'Not Elevated' test interpretation is associated with the absence of acute traumatic intracranial lesions visualized on a head CT scan.

The test is to be used with venous whole blood collected with EDTA anticoagulant in point of care or clinical laboratory settings by a healthcare professional.

The i-STAT TBI cartridge is a multiplex immunoassay that contains assays for both ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP). The assays test for the presence of these biomarkers in a whole blood sample and vield a semi-quantitative test interpretation based on measurements of both UCH-L1 and GFAP in approximately 15 minutes. The i-STAT TBI cartridge is designed to be run only on the i-STAT Alinity instrument.

The i-STAT Alinity instrument is a handheld, in vitro diagnostic device. The instrument is the main user interface of the i-STAT Alinity System and functions as the electro-mechanical interface to the test cartridge. The instrument executes the test cycle, acquires and processes the electrical sensor signals converting the signals into quantitative results. These functions are controlled by a microprocessor.

The i-STAT Alinity System is comprised of the i-STAT Alinity instrument, the i-STAT test cartridges and accessories (i-STAT Alinity Base Station, Electronic Simulator and Printer).

Assaved quality control materials are also available for use with the i-STAT TBI cartridge and include i-STAT TBI Control Level 1, i-STAT TBI Control Level 2, and the i-STAT TBI Calibration Verification Levels 1-3.

The i-STAT TBI Controls are available to monitor the performance of glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) assays on the i-STAT Alinity instrument.

The i-STAT TBI Calibration Verification Materials are available to verify the calibration of glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) assays throughout the reportable range on the i-STAT Alinity instrument.

The provided text describes the analytical and clinical performance of the i-STAT TBI cartridge with the i-STAT Alinity System, which measures GFAP and UCH-L1 to aid in the evaluation of patients with suspected mild traumatic brain injury (TBI). The information is presented to support a 510(k) premarket notification for substantial equivalence to a predicate device.

Here's an analysis of the acceptance criteria and the study proving the device meets them, based on the provided document:

1. A Table of Acceptance Criteria (Implied) and Reported Device Performance

The document does not explicitly present a "table of acceptance criteria" with predefined thresholds. Instead, it describes performance characteristics that are presumably deemed acceptable for demonstrating substantial equivalence. The core clinical performance criterion for this device, a TBI assessment test, is its ability to correctly identify patients not needing a head CT scan, which translates to high sensitivity and negative predictive value (NPV) for the absence of acute intracranial lesions.

Here's a summary of the reported core performance:

Key Implied Acceptance Criteria based on Regulatory Context:

• High Clinical Sensitivity: The device must reliably identify patients with acute intracranial lesions, minimizing false negatives to ensure patient safety and avoid missing critical injuries. A 96.5% sensitivity is presented as acceptable.
• High Negative Predictive Value (NPV): Crucially, the device's main utility is to aid in determining the need for a CT scan. A high NPV means that a "Not Elevated" result reliably indicates the absence of acute traumatic intracranial lesions. The 96.5% NPV (and higher adjusted NPV) supports this.
• Acceptable False Negative Rate: The reported 3.5% false negative rate, with the additional detail that "None of these ten (10) subjects with false negative results required surgical intervention related to their head injury as no neurosurgical lesions were identified by CT scan in these subjects," addresses a critical safety aspect.
• Analytical Performance: The document provides extensive data on analytical precision (semi-quantitative and qualitative, 20-day and multi-site), linearity, hook effect, traceability, reference interval, detection limit, analytical specificity (interference, cross-reactivity, cross-talk), and hematocrit sensitivity. These are all standard analytical performance characteristics that would need to meet predefined criteria (often internal to the manufacturer or based on regulatory guidance) to ensure the assay's reliability and robustness. While specific numerical acceptance criteria for each are not stated (e.g., "CV must be

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