Sajid M. Zafar, MD
Internal Medicine Associates
Gastroenterology
- Address
- 224 S Woods Mill Rd Ste 410, Chesterfield 63017
- Telehealth
- Not listed
- Medicare
- Not listed
- Medicaid
- Not listed
Last verified Oct 2026 Report a correction

25 listed in Chesterfield, MO · Listings last verified October 2026 · How we vet listings
We list 25 gastroenterologists, or GI doctors, in Chesterfield, part of the St. Louis area. Each listing is a physician (MD or DO) with the practice's phone number and address, so you can call to ask about insurance and wait times. For more choices nearby, see all gastroenterologists in the St. Louis area.
Internal Medicine Associates
Gastroenterology
Last verified Oct 2026 Report a correction
Gastroenterology
Last verified Oct 2026 Report a correction
Gastroenterology
Last verified Oct 2026 Report a correction
Gastroenterology
Last verified Oct 2026 Report a correction
Gastroenterology
Last verified Oct 2026 Report a correction
A gastroenterologist, or GI doctor, diagnoses and treats problems of the digestive tract: the esophagus, stomach, intestines, colon, liver, pancreas and gallbladder. People see one for heartburn that won't go away, ongoing belly pain, diarrhea or constipation, bleeding, Crohn's disease or ulcerative colitis, and for colonoscopies.
Start with the kind of care you need. Many GI doctors handle a wide range of problems, but some focus on one area:
If you're not sure, a general gastroenterologist is the right first stop. They'll refer you on if you need a subspecialist.
Check credentials. Board certification in gastroenterology shows a doctor has finished specialty training and passed a certification exam. You can look up any doctor's certification for free on the American Board of Internal Medicine website [1]. Our listings show the credentials doctors report in the federal NPI registry, but we don't verify board certification.
Know if you're due for a colonoscopy. Experts recommend colorectal cancer screening for adults ages 45 to 75 [2]. A colonoscopy is one option. Some people can start with a stool test instead. Ask your primary care doctor which test fits you, and whether your family history means you should start earlier.
Confirm insurance before you book. Practices change the plans they accept, so call the office or check your insurer's directory. HMO plans usually need a referral first. Medicare Part B covers medically necessary specialist visits; you typically pay 20% of the Medicare-approved amount after your deductible [5].
Ask where procedures are done. Colonoscopies and other scopes happen in a hospital or a separate endoscopy center. The location can change what you pay, so ask before you schedule.
Know when not to wait. Vomiting blood or material that looks like coffee grounds, black or tar-like stool, or feeling faint, confused or cold and clammy with belly symptoms need emergency care, not an appointment [4]. Call 911.
It depends on your insurance. Most HMO plans require a referral from your primary care doctor before they'll cover a specialist visit. PPO plans and traditional Medicare usually don't. Some GI practices also want a referral or recent test results before they book you, especially for a procedure, so call ahead and ask what to bring.
The U.S. Preventive Services Task Force recommends colorectal cancer screening for adults ages 45 to 75. A colonoscopy is one way to screen, and stool tests are another. People with a family history of colon cancer, certain polyps or inflammatory bowel disease may need to start earlier or screen more often. Ask your doctor what's right for you.
Yes. Medicare Part B covers a screening colonoscopy once every 120 months for most people, or once every 24 months if you're at high risk. There's no minimum age. You pay nothing for the screening if your doctor accepts assignment. If a polyp is removed during the test, you may owe a share of the cost.
Expect questions about your symptoms, diet, bowel habits, medications and family history, plus a physical exam. The doctor may order blood work, a stool test, imaging or a scope procedure such as an upper endoscopy or colonoscopy. Bring a list of your medications and any recent lab results, scans or procedure reports.
Look the doctor up on the American Board of Internal Medicine's free "Verify a Physician" tool, which shows whether they're certified in gastroenterology. Our listings show the credentials doctors report to the NPI registry, but we don't verify certification ourselves.