NPI registry status
Active
2026 NPPES data Internal Medicine Physician NPI 1255312328 M.D.
Verify on CMS → Teng Chang, M.D.
Internal Medicine Physician in Littleton, Colorado.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 172,737 in Internal Medicine Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
7K
Medicare Part D claims · 488 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
85%
generic claims · 15% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Teng Chang, M.D. filed 7,138 Medicare Part D claims in 2023 as a Internal Medicine Physician in Littleton, Colorado, prescribing 85% generic.
- 7K
- Part D claims, 2023
- 85%
- generic prescribing
- Likely
- board-certified (heuristic)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Teng Chang, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
7,138 Top 4% higher than 96% of 1,370,886 prescribers
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source CMS Medicare Part D Prescriber Public Use File · 2023
✓
Board certification likely (heuristic, not verified)
Teng Chang, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Teng Chang, M.D.?
Quality data not reportedPrimary specialty
Internal Medicine Physician
Medicare Part D claims
7,138 163% vs specialty avg
Specialty distribution in Colorado
How Internal Medicine Physician compares to other specialties among Colorado providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Internal Medicine Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Teng Chang, M.D. appears in the CMS NPPES registry as an Internal Medicine Physician provider holding M.D. credentials at 8199 SOUTHPARK LN STE 100, Littleton, CO, 80120, with a listed phone of (303) 730-3332. NPI 1255312328 was issued on 11/07/2005.
Medicare Part D records for calendar year 2023 show 7,138 prescription claims written by this provider, covering 488 Medicare beneficiaries and totaling roughly $742K in drug spend, split 15% brand-name and 85% generic by claim count, with an opioid prescribing rate of 2.4%.
Internal Medicine Physician is a high-volume specialty nationwide, with 172,737 enrolled providers across 56 states and an average of 2,716 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.
Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.
Practice Address
Provider Details
| NPI | 1255312328 |
|---|---|
| Specialty | Internal Medicine Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 11/07/2005 |
Hospital and facility affiliations
Facilities where Teng Chang, M.D. bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Optumcare Colorado Medical Group LLC
Colorado Springs, CO
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
Brand vs generic prescribing mix · Typical
Teng Chang, M.D. - brand share 15.0%
Internal Medicine Physician average
15% brand-name claims vs 85% generic, on 7,138 2023 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
7,138
Total Claims
$742K
Total Drug Cost
488
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 16,207
- Total Day Supply
- 469,654
- Brand vs Generic
- 15% brand / 85% generic
- Brand Drug Cost
- $595K
- Generic Drug Cost
- $146K
- Opioid Claims
- 168 (2.4% rate)
- Antibiotic Claims
- 277
Patient Demographics
- Average Patient Age
- 74.5 years
- Avg HCC Risk Score
- 1.21
- Gender Split
- 45% female / 55% male
- Age Distribution
- <65: 26, 65-74: 235, 75-84: 160, 85+: 67
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Teng Chang, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Atorvastatin Calcium
Atorvastatin Calcium
375 claims
- Levothyroxine Sodium
Levothyroxine Sodium
327 claims
- Amlodipine Besylate
Amlodipine Besylate
247 claims
- Rosuvastatin Calcium
Rosuvastatin Calcium
243 claims
- Losartan Potassium
Losartan Potassium
187 claims
- Metoprolol Succinate
Metoprolol Succinate
181 claims
- Omeprazole
Omeprazole
170 claims
- Metformin Hcl 148
Metformin Hcl
148 claims
| Drug | Claims |
|---|---|
| Atorvastatin Calcium | 375 |
| Levothyroxine Sodium | 327 |
| Amlodipine Besylate | 247 |
| Rosuvastatin Calcium | 243 |
| Losartan Potassium | 187 |
| Metoprolol Succinate | 181 |
| Omeprazole | 170 |
| Metformin Hcl | 148 |
| Synthroid Levothyroxine Sodium | 143 |
| Simvastatin | 139 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Internal Medicine Physician Overview
How Teng Chang, M.D. fits within the Internal Medicine Physician landscape nationally.
172,737
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider
Teng Chang, M.D.'s 7,138 claims are above the specialty average of 2,716.
Nearby Internal Medicine Physician Providers in Colorado
Other clinicians with the same primary specialty enrolled in Colorado, drawn from the same CMS NPPES roster as Chang.
Dr. Emily Aaron
MD
Denver, CO
Dr. Cynthia Abacan
MD
Pueblo, CO
Dr. David Abbey
MS MD
Fort Collins, CO
Dr. Ahmed Abdulrahman
MD
Pueblo, CO
Dr. Victor Abela
D.O.
Denver, CO
Compare Internal Medicine Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the Colorado medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Internal Medicine Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is Teng Chang, M.D.'s specialty? ▼
Teng Chang, M.D. specializes in Internal Medicine Physician and practices in Littleton, Colorado. Credentials: M.D..
How much does Teng Chang, M.D. prescribe under Medicare Part D? ▼
In 2023, Teng Chang, M.D. wrote 7,138 Medicare Part D claims totaling $742K in drug costs for 488 beneficiaries.
Where is Teng Chang, M.D. located? ▼
Teng Chang, M.D. is located at 8199 SOUTHPARK LN STE 100, Littleton, CO, 80120. Phone: (303) 730-3332.
What is Teng Chang, M.D.'s NPI number? ▼
Teng Chang, M.D.'s National Provider Identifier (NPI) is 1255312328, issued on 11/07/2005.
Does Teng Chang, M.D. prescribe more brand-name or generic drugs? ▼
Teng Chang, M.D.'s prescribing is 15% brand-name and 85% generic drugs by claim count, with $595K in brand drug costs.
Does Teng Chang, M.D. prescribe opioids? ▼
Yes, Teng Chang, M.D. had 168 opioid claims in 2023 with an opioid prescribing rate of 2.4%.
How many Internal Medicine Physician providers are there in the US? ▼
There are 172,737 Internal Medicine Physician providers across 56 states in the US. The average Internal Medicine Physician provider writes 2,716 Medicare Part D claims per year.
What drugs does Teng Chang, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Teng Chang, M.D.'s most frequently prescribed drugs include Atorvastatin Calcium, Levothyroxine Sodium, Amlodipine Besylate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Teng Chang, M.D. accept Medicare? ▼
Teng Chang, M.D. appears in CMS Medicare data with 7,138 Part D claims and 488 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Teng Chang, M.D.'s credentials? ▼
Teng Chang, M.D.'s NPI is 1255312328 with credentials M.D.. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Compiled from official public sources by the PlainDoctor editorial team.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.