Internal Medicine, Gastroenterology · San Gabriel, CA
NPI
1639146442
Since 2006
Specialty
Internal Medicine, Gastroenterology
Code 207RG0100X
Group practices
1
Medicare group memberships
Hospitals
3
Hospital affiliations
1026 E Las Tunas Dr
San Gabriel, CA, 91776
Phone (626) 287-7222
Groups this clinician bills Medicare through
Medicare paid, 2024
$240K
2,833 services
Medicare patients, 2024
801
Average age 78
Drug cost, 2024
$334K
3,267 prescriptions
Company payments, 2025
$183
From 3 companies
Procedures and visits billed to Original Medicare, 2024
In 2024, the most common Medicare service billed by Chester D Zahn was code 99213 (office e&m - established), 705 times for 325 patients. In total Chester D Zahn billed 2,833 services in 35 codes, and Medicare paid $240K.
| Code |
|---|
Official US government data: the national provider registry and Medicare enrollment records, linked by NPI. Last update of this record: 2020-03-20.
| Setting |
|---|
| Services |
|---|
| Patients |
|---|
| Paid per service |
|---|
| Medicare paid |
|---|
| 99213 Office E&M - Established | Office | 705 | 325 | $70.14 | $49K |
| 99222 Hospital E&M - Initial | Facility | 437 | 397 | $105.99 | $46K |
| 99231 Hospital E&M - Subsequent | Facility | 422 | 214 | $40.33 | $17K |
| 99232 Hospital E&M - Subsequent | Facility | 253 | 221 | $64.36 | $16K |
| 43239 Upper GI Endoscopy | Facility | 164 | 162 | $59.80 | $9,806 |
| 99204 Office E&M - New | Office | 123 | 123 | $125.04 | $15K |
| 99213 Office E&M - Established | Facility | 116 | 113 | $53.23 | $6,174 |
| 99233 Hospital E&M - Subsequent | Facility | 100 | 90 | $97.30 | $9,730 |
| 43246 Upper GI Endoscopy | Facility | 76 | 74 | $160.23 | $12K |
| G0105 Colorectal cancer screening; colonoscopy on individual at high risk | Facility | 53 | 53 | $172.88 | $9,163 |
| 45388 Lower GI Endoscopy - Other | Facility | 52 | 52 | $218.75 | $11K |
| 43255 Upper GI Endoscopy | Facility | 43 | 41 | $149.84 | $6,443 |
| 43235 Upper GI Endoscopy | Facility | 31 | 31 | $89.42 | $2,772 |
| 43251 Upper GI Endoscopy | Facility | 30 | 30 | $148.30 | $4,449 |
| 43762 Digestive/Gastrointestinal | Facility | 26 | 22 | $29.64 | $771 |
By year: 2022 $233K for 2,705 services; 2023 $252K for 2,817 services; 2024 $240K for 2,833 services.
Medicare prescription drug claims, 2024
In 2024, the drug Chester D Zahn prescribed most often to Medicare patients was Bethanechol Chloride, with 1,180 prescriptions and refills. In total Chester D Zahn wrote 3,267 Medicare prescriptions that cost $334K.
| Drug | Claims | 30-day fills | Patients | Cost |
|---|---|---|---|---|
| Bethanechol Chloride Generic | 1,180 | 2,462 | 366 | $99K |
| Omeprazole Generic | 622 | 1,348 | 186 | $6,211 |
| Isosorbide Mononitrate Er Isosorbide Mononitrate | 208 | 391 | 62 | $3,377 |
| Gavilyte-G Peg3350/Sod Sulf,bicarb,cl/Kcl | 167 | 167 | 164 | $2,714 |
| Entecavir Generic | 110 | 149 | 16 | $48K |
| Ursodiol Generic | 89 | 203 | 21 | $11K |
| Rosuvastatin Calcium Generic | 87 | 231 | 28 | $1,517 |
| Clopidogrel Clopidogrel Bisulfate | 62 | 148 | 20 | $822 |
| Montelukast Sodium Generic | 56 | 104 | 17 | $604 |
| Pantoprazole Sodium Generic | 55 | 101 | 15 | $361 |
| Famotidine Generic | 48 | 124 | 18 | $658 |
| Vemlidy Tenofovir Alafenamide | 42 | 42 | Under 11 | $57K |
| Peg-3350 And Electrolytes Peg3350/Sod Sulf,bicarb,cl/Kcl | 38 | 38 | 38 | $613 |
| Misoprostol Generic | 32 | 38 | Under 11 | $4,976 |
| Erythromycin Erythromycin Base | 26 | 26 | Under 11 | $6,941 |
Brand drugs: 156 claims; generic drugs: 3,111 claims.
Money and other things of value reported by the companies
In 2025, drug and medical device companies paid Chester D Zahn $183 ($183 in general payments such as food, travel and fees) from 3 companies. The largest payer was Gilead Sciences, Inc. with $142.
Official US government data on Original Medicare services, Medicare prescription drug plans and the payments drug and device companies must report. Services with fewer than 11 patients and drugs with fewer than 11 claims are not published. Procedure codes are shown by number with their public category.