1. (a) Identification. An Aquaporin-4 autoantibody immunological test system is a device that consists of reagents used to measure by immunochemical techniques autoantibodies in human serum samples that react with Aquaporin-4 (AQP4Ab). The measurements aid in the diagnosis of neuromyelitis optica (NMO) and neuromyelitis optica spectrum disorders (NMOSD) in conjunction with other clinical, laboratory, and radiological (e.g., magnetic resonance imaging) findings.

2. (b) Classification. Class II (special controls). The special controls for this device are:

   1. (1) Premarket notification submissions must include the following information:

      1. (i) A detailed device description including:

         1. (A) A detailed description of all components including all required ancillary reagents in the test;
         2. (B) If applicable, a detailed description of instrumentation and equipment, including illustrations or photographs of non-standard equipment or manuals;
         3. (C) If applicable, detailed documentation of the device software, including, but not limited to, standalone software applications and hardware-based devices that incorporate software;
         4. (D) A detailed description of appropriate internal and external quality controls that are recommended or provided. The description must identify those control elements that are incorporated into the specified testing procedures;
         5. (E) Detailed specifications for sample collection, processing, and storage;
         6. (F) A detailed description of methodology and assay procedure;
         7. (G) A description of how the assay cutoff (the medical decision point between positive and negative) was established and validated as well as supporting data; and
         8. (H) Detailed specification of the criteria for test results interpretation and reporting.

      2. (ii) Detailed information demonstrating the performance characteristics of the device, including:

         1. (A) Device precision/reproducibility data generated from within-run, between-run, between-day, between-lot, between-site, and total precision for multiple nonconsecutive days, as applicable. A well characterized panel of patient samples or pools from the indicated population that covers the device measuring range must be used.
         2. (B) Device linearity data generated from samples covering the device measuring range, if applicable.
         3. (C) Information on traceability to a reference material and description of value assignment of calibrators and controls, if applicable.
         4. (D) Device analytical sensitivity data, including limit of blank, limit of detection, and limit of quantitation, if applicable.
         5. (E) Device analytical specificity data, including interference by endogenous and exogenous substances, as well as cross-reactivity with samples derived from patients with other autoimmune diseases or conditions.
         6. (F) Device instrument carryover data, when applicable.
         7. (G) Device stability data, including real-time stability under various storage times and temperatures.
         8. (H) Specimen stability data, including stability under various storage times, temperatures, freeze-thaw, and transport conditions, where appropriate.
         9. (I) Method comparison data generated by comparison of the results obtained with the device to those obtained with a legally marketed predicate device with similar indications of use. A well-characterized panel of patient samples from the indicated population covering the device measuring range must be used.
         10. (J) Specimen matrix comparison data, if more than one specimen type or anticoagulant can be tested with the device. Samples used for comparison must be from well-characterized patient samples covering the device measuring range.

         11. (K) Clinical performance must be established by comparing data generated by testing samples from the indicated population and the differential diagnosis or non-target disease groups with the device to the clinical diagnostic standard.

             (1) The diagnosis of NMO and NMOSD must be based on clinical findings, laboratory tests (e.g., serological tests), and radiological tests (e.g., magnetic resonance imaging).

             (2) The differential diagnosis or non-target disease group must include the applicable diseases or conditions, including but not be limited to the following: Multiple sclerosis, stroke, Lyme disease, shingles, syphilis, human immunodeficiency virus, hepatitis B, tuberculosis, Srgen's syndrome, systemic lupus erythematous, systemic vasculitis, sarcoidosis, Graves' disease, Hashimoto's disease, Type I diabetes, rheumatoid arthritis, Addison's disease, and myasthenia gravis.

             (3) Diagnosis of diseases or conditions for the differential or non-target disease groups must be based on established diagnostic criteria and clinical evaluation.

             (4) For all samples, the diagnostic clinical criteria and the demographic information must be collected and provided.

             (5) The clinical validation results must demonstrate clinical sensitivity and clinical specificity for the test values based on the presence or absence of NMO and NMOSD.

             (6) The data must be summarized in tabular format comparing the interpretation of results to the disease status.

         12. (L) Expected/reference values generated by testing an adequate number of samples from apparently healthy normal individuals.
      3. (iii) Identification of risk mitigation elements used by the device, including description of all additional procedures, methods, and practices incorporated into the directions for use that mitigate risks associated with testing.

   2. (2) The device's 21 CFR 809.10(b) compliant labeling must include warnings relevant to the device including:

      1. (i) A warning statement that reads “The device is for use by laboratory professionals in a clinical laboratory setting”; and
      2. (ii) A warning statement that reads “The device is not to be used as a stand-alone device but as an adjunct to other clinical information. A diagnosis of Neuromyelitis Optica (NMO) and Neuromyelitis Optica Spectrum Disorders (NMOSD) should not be made on a single test result. The clinical symptoms, results from physical examination, laboratory tests (e.g., serological tests), and radiological tests (e.g. Magnetic Resonance Imaging), when appropriate, should always be taken into account when considering the diagnosis of NMO and NMOSD.”
   3. (3) The device's 21 CFR 809.10(b) compliant labeling must include a detailed description of the protocol and performance studies performed in accordance with paragraph (b)(1)(ii) of this section and a summary of the results.

[82 FR 50076, Oct. 30, 2017]