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  • About
      About Our Clinic

      Meet Dr. Peterson

      Get to know Dr. Ralph L. Peterson and the MacArthur Gastroenterology team, along with our approach to digestive and liver health care.

      Portrait of Dr. Ralph Peterson, gastroenterologist at MacArthur Gastroenterology in Oakland
      Dr. Ralph L. Peterson, MD

      Gastroenterologist

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      MacArthur Gastroenterology Inc.
      10520 MacArthur Blvd.
      Oakland, CA 94605

      (510) 562-7467

  • Services
      Our Services

      Care built around you

      Four ways we support your digestive and liver health, each with a dedicated page.

      Gastroenterology

      Comprehensive digestive health, screening, and treatment.

      Weight Management

      Physician-supervised weight loss, GLP-1 support, and coaching.

      MASLD / Fatty Liver Scanning

      Fast, non-invasive liver fat and stiffness screening.

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  • Weight Management

      Weight Management

      Patient celebrating progress in the Weight Management program
      Weight Management

      Lose weight. Feel better. Live healthier.

      A physician-supervised program combining medical evaluation, personalized coaching, and compounded GLP-1 support when clinically appropriate.

      Explore the program →
  • MASLD / Liver Scan

      MASLD / Liver Scan

      Liver scan procedure at MacArthur Gastroenterology
      MASLD / Fatty Liver

      A 10-minute scan that can change your outlook

      Our in-office ultrasound-based scan measures liver fat and stiffness in minutes, with no needles, no sedation, and results the same day.

      Learn about the liver scan →
  • Contact
      Contact Us

      We're here to help

      Reach our front desk directly, or send a message and our team will follow up.

      (510) 562-7467
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      Contact form, response within 1 business day

      10520 MacArthur Blvd., Oakland, CA 94605
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      Office Hours
      Monday:
      9:00 AM to 3:30 PM;
      3:30 PM to 6:00 PM by appointment only.
      Tuesday:
      7:30 AM to 3:30 PM;
      3:30 PM to 6:00 PM by appointment only.
      Wednesday:
      9:00 AM to 3:30 PM;
      3:30 PM to 6:00 PM by appointment only.
      Thursday:
      9:00 AM to 3:30 PM;
      3:30 PM to 6:00 PM by appointment only.
      Friday:
      9:00 AM to 2:00 PM;
      By appointment only.
      Saturday:
      9:00 AM to 2:00 PM;
      By appointment only.
      Sunday: Closed.
  • Make a Payment
      Billing

      Pay your bill securely online

      View your balance and make a payment anytime, no portal login required.

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      Billing questions: (510) 562-7467

  • Patient Portal
      What you can do in the portal
      • Message your care team securely
      • View lab and test results
      • Manage appointments and get reminders
      • Request prescription refills
      • Complete forms before your visit
      • Join telehealth visits and pay bills

      Click here for more info about the portal →

      Patients

      Access the MacArthur GI Patient Portal

      Message your care team, view test results, request refills, and manage appointments from your secure patient account.

      Access patient portal →

      New patient? Ask our front desk for portal access at your first visit.

Nondiscrimination Notice and Language Assistance

Effective date: October 29, 2026

Notice of Nondiscrimination

MacArthur Gastroenterology Inc. (Mac GI) complies with applicable federal civil rights laws and does not discriminate on the basis of race, color, national origin (including limited English proficiency and primary language), age, disability or sex. Mac GI does not exclude people or treat them differently because of race, color, national origin, age, disability or sex.

Free help for people with disabilities

Mac GI provides people with disabilities reasonable modifications and free, appropriate auxiliary aids and services to communicate effectively with us, such as:

  • Qualified sign language interpreters
  • Written information in other formats, such as large print, audio and accessible electronic formats

Free language help

Mac GI provides free language assistance services to people whose primary language is not English, such as:

  • Qualified interpreters
  • Information written in other languages

If you need reasonable modifications, appropriate auxiliary aids and services, or language assistance services, call our office at (510) 562-7467 or contact our Section 1557 Coordinator below. Please tell us when you book so we can have help ready for your visit.

How to file a grievance

If you believe that Mac GI has failed to provide these services or discriminated against you in another way on the basis of race, color, national origin, age, disability or sex, you can file a grievance with:

Section 1557 Coordinator
MacArthur Gastroenterology Inc. (Mac GI)
10520 MacArthur Blvd., Oakland, CA 94605
Phone: (510) 562-7467
Email: info@macarthurgi.com

You can file a grievance in person, by mail or by email. If you need help filing a grievance, our Section 1557 Coordinator is available to help you.

How to file a complaint with the federal government

You can also file a civil rights complaint with the U.S. Department of Health and Human Services, Office for Civil Rights:

  • Online: ocrportal.hhs.gov/ocr/portal/lobby.jsf
  • By mail: U.S. Department of Health and Human Services, 200 Independence Avenue SW, Room 509F, HHH Building, Washington, D.C. 20201
  • By phone: 1-800-368-1019, 800-537-7697 (TDD)

Complaint forms are available at hhs.gov/ocr/complaints.

This notice is available at macarthurgi.com/nondiscrimination-notice and at our front desk.

Notice of Availability of Language Assistance Services and Auxiliary Aids and Services

English: ATTENTION: If you speak another language, free language assistance services are available to you. Appropriate auxiliary aids and services to provide information in accessible formats are also available free of charge. Call (510) 562-7467 or speak to our front desk staff.

Español (Spanish): ATENCIÓN: Si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. También ofrecemos ayudas y servicios auxiliares gratuitos para brindar información en formatos accesibles. Llame al (510) 562-7467.

繁體中文 (Chinese): 注意:如果您使用繁體中文,您可以免費獲得語言援助服務。我們亦免費提供輔助工具和服務,以無障礙格式提供資訊。請致電 (510) 562-7467。

Tiếng Việt (Vietnamese): CHÚ Ý: Nếu bạn nói Tiếng Việt, có các dịch vụ hỗ trợ ngôn ngữ miễn phí dành cho bạn. Chúng tôi cũng cung cấp miễn phí các phương tiện và dịch vụ hỗ trợ phù hợp để cung cấp thông tin ở các định dạng dễ tiếp cận. Gọi số (510) 562-7467.

Tagalog: PAUNAWA: Kung nagsasalita ka ng Tagalog, maaari kang gumamit ng mga serbisyo ng tulong sa wika nang walang bayad. Mayroon ding libreng angkop na mga auxiliary aid at serbisyo para magbigay ng impormasyon sa mga accessible na format. Tumawag sa (510) 562-7467.

한국어 (Korean): 주의: 한국어를 사용하시는 경우, 언어 지원 서비스를 무료로 이용하실 수 있습니다. 접근 가능한 형식으로 정보를 제공하기 위한 적절한 보조 기구 및 서비스도 무료로 제공됩니다. (510) 562-7467 번으로 전화해 주십시오.

Հայերեն (Armenian): ՈՒՇԱԴՐՈՒԹՅՈՒՆ՝ Եթե խոսում եք հայերեն, ապա ձեզ անվճար կարող են տրամադրվել լեզվական աջակցության ծառայություններ: Զանգահարեք (510) 562-7467:

فارسی (Persian): توجه: اگر به زبان فارسی گفتگو می کنید، تسهیلات زبانی بصورت رایگان برای شما فراهم می باشد. با (510) 562-7467 تماس بگیرید.

Русский (Russian): ВНИМАНИЕ: Если вы говорите на русском языке, то вам доступны бесплатные услуги перевода. Также бесплатно предоставляются вспомогательные средства и услуги для получения информации в доступных форматах. Звоните (510) 562-7467.

日本語 (Japanese): 注意事項:日本語を話される場合、無料の言語支援をご利用いただけます。アクセシブルな形式で情報を提供するための補助具やサービスも無料でご利用いただけます。(510) 562-7467 までお電話ください。

العربية (Arabic): ملحوظة: إذا كنت تتحدث العربية، فإن خدمات المساعدة اللغوية تتوافر لك بالمجان. اتصل برقم (510) 562-7467.

ਪੰਜਾਬੀ (Punjabi): ਧਿਆਨ ਦਿਓ: ਜੇ ਤੁਸੀਂ ਪੰਜਾਬੀ ਬੋਲਦੇ ਹੋ, ਤਾਂ ਭਾਸ਼ਾ ਵਿੱਚ ਸਹਾਇਤਾ ਸੇਵਾ ਤੁਹਾਡੇ ਲਈ ਮੁਫਤ ਉਪਲਬਧ ਹੈ। (510) 562-7467 ‘ਤੇ ਕਾਲ ਕਰੋ।

ភាសាខ្មែរ (Khmer): ប្រយ័ត្ន៖ បើសិនជាអ្នកនិយាយ ភាសាខ្មែរ សេវាជំនួយផ្នែកភាសា ដោយមិនគិតឈ្នួល គឺអាចមានសំរាប់បំរើអ្នក។ ចូរ ទូរស័ព្ទ (510) 562-7467។

Hmoob (Hmong): LUS CEEV: Yog tias koj hais lus Hmoob, cov kev pab txog lus, muaj kev pab dawb rau koj. Hu rau (510) 562-7467.

हिंदी (Hindi): ध्यान दें: यदि आप हिंदी बोलते हैं तो आपके लिए मुफ्त में भाषा सहायता सेवाएं उपलब्ध हैं। (510) 562-7467 पर कॉल करें।

ภาษาไทย (Thai): เรียน: ถ้าคุณพูดภาษาไทย คุณสามารถใช้บริการช่วยเหลือทางภาษาได้ฟรี โทร (510) 562-7467

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Compassionate, preventive digestive and liver care for the Bay Area.

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Contact

10520 MacArthur Blvd.
Oakland, CA 94605

(510) 562-7467

Fax: (510) 227-6895

info@macarthurgi.com

Send us a message →

Office Hours

Monday:
9:00 AM to 3:30 PM;
3:30 PM to 6:00 PM by appointment only.
Tuesday:
7:30 AM to 3:30 PM;
3:30 PM to 6:00 PM by appointment only.
Wednesday:
9:00 AM to 3:30 PM;
3:30 PM to 6:00 PM by appointment only.
Thursday:
9:00 AM to 3:30 PM;
3:30 PM to 6:00 PM by appointment only.
Friday:
9:00 AM to 2:00 PM;
By appointment only.
Saturday:
9:00 AM to 2:00 PM;
By appointment only.
Sunday: Closed.

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