Dr. Mark Harold Kogan, MD

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

• Alta Bates Summit Medical Center Hospital · Oakland, CA
• Alta Bates Summit Medical Center - Alta Bates Camp Hospital · Berkeley, CA · listed as Alta Bates Summit Medical Center
• Contra Costa Regional Medical Center Hospital · Martinez, CA
• Ridgecrest Regional Hospital Hospital · Ridgecrest, CA

Colleagues at Ridgecrest Regional Hospital

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 94 clinicians in the practice; 12 are shown here.

• Dr. Alex Travis Allwein, MD Emergency Medicine Physician · Chula Vista, CA
• Arjun Chandrasekaran, MD Surgery Physician · Redding, CA
• Jeffrey George Cusson Certified Registered Nurse Anesthetist · Fresno, CA
• Dr. Ernest V De Guzman, MD Psychiatry Physician · San Diego, CA
• Megan Joy Kajiwara, WHNP Women's Health Nurse Practitioner · Ridgecrest, CA
• Dr. Prashanth Vasantha Kumar, MD Nephrology Physician · Victorville, CA
• Mai K Lai, MD Emergency Medicine Physician · Pasadena, CA
• Dr. Thien-Trang Joanna Nguyen, MD Plastic and Reconstructive Surgery Physician · West Hollywood, CA
• Daan Ren, MD Family Medicine Physician · Stockton, CA
• Dr. Anne Kathryn Schuckman, MD Urology Physician · Los Angeles, CA
• Andjine Vanbokkelen Family Nurse Practitioner · Groton, CT
• Anthony Michael Woolf, MD Emergency Medicine Physician · Miramar Beach, FL

Other providers in San Pablo

• Center for Digestive Disorders

  Organization Gastroenterology Physician · NPI 1669559639

  2089 Vale Rd Ste 33 Ste 33, San Pablo, CA 94806-3850 · (510) 234-5012

• Insite Digestive Health Care

  Organization Gastroenterology Physician · NPI 1831690304

  2089 Vale Rd Ste 33, San Pablo, CA 94806-3850 · (510) 234-5012

• Kiran Fatima Narsinh, MD

  Individual Gastroenterology Physician · NPI 1730316977

  2089 Vale Rd Ste 33, San Pablo, CA 94806-3847 · (510) 234-5012

• Dr. Jacqueline Jeeyung Park, MD

  Individual Gastroenterology Physician · NPI 1346415247

  2089 Vale Rd Ste 33, San Pablo, CA 94806-3847 · (510) 234-5012

• Dr. Gerald Neil Schaffer, MD

  Individual Gastroenterology Physician · NPI 1780797027

  2089 Vale Rd Ste 33, San Pablo, CA 94806-3847 · (510) 234-5012