← Product Code [NST](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/NST) · K042248 # KRONUS, INC.'S ACETYLCHOLINE RECEPTOR ANTIBODY (ACHRAB) ASSAY KIT (K042248) _Kronus Market Development Associates, Inc. · NST · Dec 17, 2004 · Immunology · SESE_ **Canonical URL:** https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/NST/K042248 ## Device Facts - **Applicant:** Kronus Market Development Associates, Inc. - **Product Code:** [NST](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/NST.md) - **Decision Date:** Dec 17, 2004 - **Decision:** SESE - **Submission Type:** Traditional - **Regulation:** 21 CFR 866.5660 - **Device Class:** Class 2 - **Review Panel:** Immunology ## Intended Use The Kronus I¹²⁵ Acetylcholine Receptor Antibody (AChRAb) Assay Kit is for the semi-quantitative determination of acetylcholine receptor antibody in human serum. The AChRAb Assay kit is useful as an aid in the differential diagnosis of Myasthenia Gravis (MG). ## Device Story The Kronus I¹²⁵ AChRAb Assay Kit is a semi-quantitative radioimmunoassay (RIA) used to detect acetylcholine receptor autoantibodies in human serum. The device utilizes detergent-solubilized fetal and adult acetylcholine receptors extracted from rhabdomyosarcoma cells, labeled with I¹²⁵ alpha-bungarotoxin. Patient serum is incubated with these labeled receptors; autoantibodies bind to the receptors. The resulting complexes are immunoprecipitated using goat anti-human IgG. After centrifugation, the radioactivity of the pellet is measured via a gamma counter. The measured radioactivity is directly proportional to the concentration of autoantibodies present. The assay is performed in a clinical laboratory setting. Results assist clinicians in the differential diagnosis of Myasthenia Gravis. The device provides a quantitative measurement of toxin-bound receptors, aiding in the clinical assessment of autoimmune status. ## Clinical Evidence No clinical data provided in the summary document; substantial equivalence established via bench testing and performance characteristics typical of immunological assay kits. ## Technological Characteristics Radioreceptor immunoassay (RIA) using I¹²⁵-labeled alpha-bungarotoxin. Reagents include detergent-solubilized fetal and adult acetylcholine receptors from rhabdomyosarcoma cells. Detection via gamma counter. Measuring range 0.3 to 7.0 nmol/L. Manual liquid-phase incubation and immunoprecipitation workflow. ## Regulatory Identification A multiple autoantibodies immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoantibodies (antibodies produced against the body's own tissues) in serum and other body fluids. Measurement of multiple autoantibodies aids in the diagnosis of autoimmune disorders (disease produced when the body's own tissues are injured by autoantibodies). ## Submission Summary (Full Text) > This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com. > > Innolitics is a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices, including [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/). {0}------------------------------------------------ DEPARTMENT OF HEALTH & HUMAN SERVICES Image /page/0/Picture/1 description: The image shows the seal of the U.S. Department of Health & Human Services. The seal features a stylized eagle with three curved lines representing its body and wings. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES (USA)" are arranged in a circular pattern around the eagle. Public Health Service Food and Drug Administration 2098 Gaither Road Rockville MD 20850 DEC 17 2004 Heather Viele Director of Technical Affairs Kronus Market Development Associates, Inc. 12554 West Bridger St., Suite 108 Boise, ID 83713 Re: k042248 Trade/Device Name: Kronus I125 Acetylcholine Receptor antibody Kit Regulation Number: 21 CFR 866.5660 Regulation Name: Multiple Autoantibodies Immunological Test System Regulatory Class: Class II Product Code: NST Dated: August 16, 2004 Received: August 19, 2004 Dear Ms Viele: We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050. {1}------------------------------------------------ Page 2 - Ms. Heather Viele This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market. If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Office of Compliance at (240) 276-3084. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html Sincerely yours, Robert L. Becker Jr. Robert L. Becker, Jr., M.D., Ph. Director Division of Immunology and Hematology Devices Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health Enclosure {2}------------------------------------------------ ## Indications for Use 510(k) Number (if known): ## K042248 Device Name: Acetylcholine Receptor Antibody (AChRAb) Assay Kit Indications For Use: The KRONUS Acetylcholine Receptor Antibody (AChRAb) Assay Kit is for the quantitative or qualitative determination of acetylcholine receptor antibody in human serum. The KRONUS Acetylcholine Receptor Antibody(AChRAb) kit is useful as an aid in the differential diagnosis of Myasthenia Gravis. Prescription Use X (Part 21 CFR 801 Subpart D) AND/OR Over-The-Counter Use (21 CFR 807 Subpart C) (PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED) Concurrence of CDRH, Office of In Vitro Diagnostic Devices (OIVD) Maria In Clem Dhdelen Sign Off Division Sign-Off Office of In Vitro Diagnostic Device Evaluation and Safety Page 1 of _ | _ | _ | _ | | 510(k) K042248 --- **Source:** [https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/NST/K042248](https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/NST/K042248) **Published by [Innolitics](https://innolitics.com)** — a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices. 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