Physician Profile
Chester D. Zahn, MD
Unclaimed ProfileAbout Dr. Zahn
Chester D. Zahn, MD practices gastroenterology in San Gabriel, CA. Chester is a 1983 graduate of Stanford University School of Medicine. According to Medicare claims data, Chester cared for 2,069 Medicare patients across 2,761 services. The services billed most often include established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more, initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes, and subsequent hospital care with straightforward or low level of medical decision making, per day, if using time, at least 25 minutes.
Summarised automatically from public NPI registry and CMS Medicare data. Not written or reviewed by this provider. Claim this profile to replace it — free, and no identity document with a practice or institutional email.
Education & Training
Specialty
Credentials & Licensing
License numbers are what the provider reported to NPPES when the NPI was issued or updated. NPPES does not verify licensure; confirm current standing with the state licensing board.
Medicare information
Exactly as CMS reports it (National Downloadable File, Opt-Out Affidavits, Order & Referring). Not an insurance directory; confirm coverage with the office.
Contact Information
- (626) 287-7222
- Email not available
Practice Locations
1026 E LAS TUNAS DR
San Gabriel, CA 91776
Conditions Commonly Evaluated or Treated
Within Gastroenterology generally. Availability varies by clinician, training and location — this profile has not been claimed, so nothing here is a personal claim by the provider.
Conditions
Most searched conditions
- Acid reflux
- Celiac disease
- Crohn's disease
- Hemorrhoids
- IBS
- Swallowing difficulties
- Ulcerative colitis
Biliary and pancreas
- Acute pancreatitis
- Gallstones
- Pancreatic cysts
- Primary sclerosing cholangitis
Colon and anorectal
- Anal fissure
- Colon cancer
- Colon polyps
- Lower gastrointestinal bleeding
Esophagus and swallowing
- Barrett's esophagus
- Eosinophilic esophagitis
- Esophageal stricture
- Esophagitis
Functional bowel and motility
- Chronic diarrhea
- Fecal incontinence
- Small intestinal bacterial overgrowth
Liver
- Ascites
- Autoimmune hepatitis
- Cirrhosis
- Fatty liver disease
- Hemochromatosis
- Hepatitis B
- Hepatitis C
- Portal hypertension
Stomach and duodenum
- Functional dyspepsia
- Gastritis
- Gastroparesis
- H. pylori infection
- Peptic ulcer disease
Bowel & Colon
- Diverticulitis
Digestive Symptoms
- Constipation
Gallbladder & Bile Ducts
- Blocked Bile Duct
Procedures & services
Most searched procedures
- Colonoscopy
- Endoscopy
- Gallbladder removal
- Hernia repair
- Liver biopsy
Lower endoscopy
- Colon polyp removal
- Endoscopic control of gastrointestinal bleeding
- Flexible sigmoidoscopy
Upper endoscopy
- Endoscopic submucosal dissection
- Esophageal dilation
Capsule and physiology testing
- Anorectal manometry
- Capsule endoscopy
- Esophageal manometry
Diagnostic Testing
- 24-Hour Acid Reflux Test
- EUS-Guided Fine Needle Biopsy
- H. Pylori Breath Test
- SIBO Breath Test
Liver procedures
- Esophageal variceal banding
- Liver elastography
- Paracentesis
Treatments
- Stool Transplant
Procedures Most Often Billed to Medicare
2,761 services · 2,069 patients · 22 distinct codes
| Procedure | Type | Code | Services | Compared with peers |
|---|---|---|---|---|
| Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope | Procedure | 43239 |
164 | More than most peers in Gastroenterology |
| Insertion of stomach tube using a flexible endoscope | Procedure | 43246 |
76 | More than most peers in Gastroenterology |
| Destruction of polyp or growth of large bowel using a flexible endoscope | Procedure | 45388 |
52 | More often than most peers in Gastroenterology |
| Control of bleeding of esophagus, stomach, and/or upper small bowel using a flexible endoscope | Procedure | 43255 |
43 | More than most peers in Gastroenterology |
| Diagnostic exam of esophagus, stomach, and/or upper small bowel using a flexible endoscope | Procedure | 43235 |
31 | More often than most peers in Gastroenterology |
| Removal of polyps or growths of esophagus, stomach, and/or upper small bowel using an endoscope with mechanical snare | Procedure | 43251 |
30 | More often than most peers in Gastroenterology |
| Replacement of stomach stoma tube | Procedure | 43762 |
26 | As often as other peers in Gastroenterology |
| Incision of pancreatic outlet using a flexible endoscope | Procedure | 43262 |
21 | More often than most peers in Gastroenterology |
| Balloon dilation of pancreatic or bile duct or sphincter using a flexible endoscope | Procedure | 43277 |
20 | More often than most peers in Gastroenterology |
| Repositioning of oral or nasal feeding tube in small bowel | Procedure | 43761 |
19 | Too few peers to compare |
Source: CMS Medicare public data. Shows how often procedures were billed — not quality of care or patient satisfaction.
Related providers
Connections drawn from the registry and from what providers have told us. A link here is not a referral or an endorsement.
Also at this address 1
Providers at the same street address. Each files their own registry entry, so a shared practice often appears under several different names.
Other gastroenterologists in San Gabriel 2
Same specialty, same city.
Trained at Stanford University School of Medicine 8
Other providers in the same specialty who trained at the same institution.
More connections — 16 related providers in 2 groups
Class of 1983 at Stanford University School of Medicine 8
Providers who graduated from the same medical school in the same year.
Also performs Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope 8
Providers in CA who bill this service to Medicare most often.
Common questions
What does Dr. Zahn specialize in?
Dr. Zahn is a gastroenterologist in San Gabriel, CA. That is the designation recorded for this NPI in the federal registry, where it is listed as “Gastroenterology”.
NPI registry
Where is Dr. Zahn located?
Dr. Zahn is listed at 1026 E Las Tunas Dr, San Gabriel, CA 91776. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
What is Dr. Zahn's phone number?
The number on file is (626) 287-7222. Guide.md cannot book appointments or pass on messages — please call the office directly.
NPI registry
What is Dr. Zahn's NPI number?
Dr. Zahn's National Provider Identifier is 1639146442. It is issued by the Centers for Medicare & Medicaid Services and is unique and permanent — it does not change if they move practice.
NPI registry
Where did Dr. Zahn go to medical school?
Dr. Zahn attended Stanford University School of Medicine, graduating in 1983. This comes from the CMS National Downloadable File.
CMS public data
How long has Dr. Zahn been practicing?
Dr. Zahn has 43 years experience. Calculated from a graduation year of 1983, reported in the CMS National Downloadable File.
CMS public data
What does Dr. Zahn do most often?
According to Medicare billing data, Dr. Zahn performs procedures including biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope, insertion of stomach tube using a flexible endoscope and destruction of polyp or growth of large bowel using a flexible endoscope, alongside routine visits and testing. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has Dr. Zahn confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Dr. Zahn. If this is you, claiming it is free.
Guide.md
Provider data sourced from the NPPES NPI Registry and CMS public datasets. Information is provided for reference and is not medical advice.