DR. MARK W DREYER M.D.
NPI 1396714861
Internal Medicine - Gastroenterology in Waukesha, WI
NPI Status: Active since March 16, 2006
Contact Information
1111 DELAFIELD ST
SUITE 212
WAUKESHA, WI
ZIP 53188
Phone: (262) 544-8622
Fax: (262) 544-8630
NPPES record last updated: August 12, 2014. Verified against the NPPES registry weekly; last sync: July 12, 2026.
- Individual
- Male
- Internal Medicine
- Gastroenterology
About MARK DREYER
This page provides the complete NPI Profile along with additional information for Mark Dreyer, an internist established in Waukesha, Wisconsin with a medical specialization in Internal Medicine, focusing in gastroenterology . The healthcare provider is registered in the NPI registry with number 1396714861 assigned on March 2006. The practitioner's primary taxonomy code is 207RG0100X with license number 23754-020 (WI). The provider is registered as an individual and his NPI record was last updated 12 years ago.
- NPI
- 1396714861
- Provider Name
- DR. MARK W DREYER M.D.
- Gender
- Male
- Entity Type
- Individual
- Location Address
- 1111 DELAFIELD ST SUITE 212 WAUKESHA, WI 53188
- Location Phone
- (262) 544-8622
- Location Fax
- (262) 544-8630
- Mailing Address
- 1111 DELAFIELD ST SUITE 212 WAUKESHA, WI 53188
- Mailing Phone
- (262) 544-8622
- Mailing Fax
- (262) 544-8630
- Is Sole Proprietor?
- No
- Enumeration Date
- 03-16-2006
- Last Update Date
- 08-12-2014
- Code Navigator
An internist like Mark Dreyer is a physician who has completed an internal medicine residency and is board-certified or board-eligible in an internist specialty. Internists are trained to care for adults of all ages for many different medical conditions. An internist typically monitors chronic physical conditions, identifies acute diseases, provides family planning, provides counseling about wellness and disease prevention, etc.
Location Map
Specialty - Primary Taxonomy
The NPI enumerator requires providers to submit at least one taxonomy code. A taxonomy code is a unique 10-character code that describes the healthcare provider type, classification, and the area of specialization. There could be only one primary taxonomy code per NPI record. For individual NPIs the license data is associated to the taxonomy code.
- Classification
Internal Medicine Gastroenterology
- Taxonomy Code
- 207RG0100X
- Type
- Allopathic & Osteopathic Physicians
- License No.
- 23754-020
- License State
- WI
- Taxonomy Description
- An internist who specializes in diagnosis and treatment of diseases of the digestive organs including the stomach, bowels, liver and gallbladder. This specialist treats conditions such as abdominal pain, ulcers, diarrhea, cancer and jaundice and performs complex diagnostic and therapeutic procedures using endoscopes to visualize internal organs.
Insurance Plans Accepted
According to publicly available information the provider might be accepting the following health plans from these health insurance companies:
Specific plan information not avaialable, please contact the provider to verify if your insurance plan is accepted.
Specific plan information not avaialable, please contact the provider to verify if your insurance plan is accepted.
*Please verify directly with this provider to make sure your insurance plan is currently accepted.
Additional Identifiers
The NPI Enumerator encourages providers to submit additional identifiers with their NPI application although the submission of this information is optional. The additional identifier(s) section includes other numbers or codes currently or formerly used as an identifier for the provider by other public healthcare entities. The identifiers may include UPIN, NSC, OSCAR, DEA, Medicaid State or PIN identification numbers.
| Identifier | Type / Code | Identifier State | Identifier Issuer |
|---|---|---|---|
| 30411200 | MEDICAID (05) | WI | |
| 100006904 | MEDICARE PIN (08) | WI | |
| 000168085 | MEDICARE PIN (08) | WI | |
| B52519 | MEDICARE UPIN (02) | WI |
Reviews for DR. MARK W DREYER M.D.
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NPI Number Validation
How NPI Validation Works
The NPI validation process uses the ISO-standard Luhn algorithm, a mathematical "handshake", to ensure that a provider's 10-digit ID is authentic and free of common typing errors.
To verify the NPI 1396714861, we treat the final digit (1) as the Check Digit—the target answer we need to reach. The process begins by taking the first nine digits and adding a constant value of 24, which accounts for the "80840" prefix required for all U.S. health identifiers. We then double every other digit starting from the right and sum the individual digits of those results together. For this specific NPI, that total comes to 69. The final step is to find the difference between that total and the next multiple of ten (70 - 69 = 1).
Digit-by-digit view
Use the first nine digits for the calculation. Starting from the right, double every other digit. The last digit is the check digit and is not part of the calculation.
Step 1: Double every other digit from the right
Starting with the rightmost digit of the first nine digits, double every other value. If doubling creates a two-digit number, add those digits together.
Step 2: Add all digits plus the NPI constant
Add the transformed values, the unchanged digits, and the constant 24.
Step 3: Find the amount needed to reach the next multiple of 10
The next multiple of ten after 69 is 70. The difference is the calculated check digit.
Other Providers at the Same Location
The following 20 providers are registered at the same or a nearby location.
WAUKESHA, WI 53188
WAUKESHA, WI 53188
WAUKESHA, WI 53188
WAUKESHA, WI 53188
WAUKESHA, WI 53188
WAUKESHA, WI 53188
WAUKESHA, WI 53188
WAUKESHA, WI 53188
WAUKESHA, WI 53188
WAUKESHA, WI 53188
WAUKESHA, WI 53188
Frequently Asked Questions
The NPI number assigned to this healthcare provider is 1396714861, enumerated as an "individual" on March 16, 2006.
The provider is located at 1111 DELAFIELD ST SUITE 212 WAUKESHA, WI 53188 and the phone number is (262) 544-8622.
Internal Medicine with taxonomy code 207RG0100X and a focus in Gastroenterology.
The provider might be accepting Accepts: Medicare and Medicaid. Please consult your insurance carrier or call the provider to verify.
