Dr. Alexandra Guillaume, MD

Dr. Guillaume practices at Stony Brook University Hospital in Stony Brook, New York, part of Stony Brook University.

Dr. Guillaume's NPI, 1396981197, was assigned on December 29, 2008. Dr. Guillaume graduated from Tufts University School Of Medicine in 2006. Dr. Guillaume holds New York license 254256.

Dr. Guillaume's primary practice is Stony Brook University Hospital, at Health Sciences Center Suny, Stony Brook, NY 11794 in Suffolk County. The practice phone is (631) 444-4000. Dr. Guillaume also practices at Stony Brook University Hospital, 101 Nicolls Rd, Stony Brook, NY 11794.

Dr. Guillaume's primary practice is Stony Brook University Hospital in Stony Brook, New York, part of Stony Brook University. Dr. Guillaume is also affiliated with North Shore University Hospital. The medical group on file is Stony Brook Internists. Dmand AI also links Dr. Guillaume to 3 more hospitals, 6 medical groups, 2 group practices and clinics and 1 clinical lab, each named with a free account.

Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Guillaume practices, 8 sites in all. Vendor and product names are available with a free account.

Gastroenterology is Dr. Guillaume's primary specialty in the NPI Registry, under taxonomy code 207RG0100X. Dr. Guillaume is board certified in gastroenterology by the American Board of Internal Medicine. Dmand AI has Dr. Guillaume's licenses on file in 2 states: New York and Wisconsin.

Dmand AI lists acid reflux, acute gastroduodenitis, chronic indigestion, cirrhosis, colonoscopy, fatty liver, gastroduodenitis and gastroenteritis among the conditions Dr. Guillaume treats.

CMS data shows 439 Medicare services from Dr. Guillaume across 14 procedure codes in 2024, for 286 Medicare patients. Medicare paid $40,090 for them.

CMS counts 286 Medicare patients who saw Dr. Guillaume in 2024. The largest group is 65 to 74, with 114 patients. 75% of them have high blood pressure, and 75% have high cholesterol. 21% are also on Medicaid. Their average risk score is 1.74, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.

Across all payers, Dmand AI patient panel data puts Dr. Guillaume's median patient age at 65, with 66% women.

In 2024, Dr. Guillaume wrote 450 Medicare Part D claims for 113 patients. 64% of them were for generic drugs. CMS names the drug for 302 of them, across 10 drugs with 11 or more claims each, at $138,499 in total drug cost. In 2023, CMS named 480 claims across 16 drugs.

Dr. Guillaume accepts Medicare assignment, so Medicare's approved amount is taken as full payment. CMS lists Dr. Guillaume as offering telehealth. CMS counts 81 procedures of upper gastrointestinal (gi) endoscopy for acid reflux by Dr. Guillaume, more than 72% of the clinicians it reports for that procedure.

Dmand AI links 10 papers to Dr. Guillaume, published from 2012 to 2024. 2020 was the busiest year, with 2. Dr. Guillaume has published most often in Ann N Y Acad Sci. Dr. Guillaume's most frequent co-authors are Bani Chander Roland, MD, Maksim Agaronov, MD and Dan Elison Azagury, MD.

CMS Open Payments shows 363 general payments to Dr. Guillaume from 40 drug and device companies from 2016 to 2025. Food and beverage make up the largest share, 71% of the total. Allergan Inc. paid the most, $5,963.

Dr. Guillaume graduated from Tufts University School Of Medicine in 2006.

Dr. Guillaume is in network with 18 carriers, including Aetna, Excellus BlueCross BlueShield and MVP Health Care. HMO plans come from the most carriers, 10. Check the plan with the practice before a visit.