Timothy Wassenaar, MD
NPI 1518928993 · Hematology & Oncology Physician · Waukesha, WI
Enrolled with Medicare as Practitioner - Hematology/Oncology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Timothy Wassenaar, MD is a Hematology & Oncology Physician provider in Waukesha, WI (NPI 1518928993).
Provider details
- NPI number
- 1518928993
- Entity type
- Individual
- Primary specialty
- Hematology & Oncology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 46327 (WI)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
20 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
620 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 150 | $90 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 107 | $134 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 81 | $73 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 73 | $90 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 50 Minutes99233 | 63 | $109 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 31 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Acyclovir | 198 | 46 |
| Apixabanbrand: Eliquis | 139 | 22 |
| Hydroxyurea | 126 | 27 |
| Dexamethasone | 63 | 19 |
| Lenalidomidebrand: Revlimid | 58 | — |
| Warfarin Sodium | 53 | 14 |
| Imatinib Mesylate | 45 | — |
| Ibrutinib |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-03-28
- Last updated
- 2024-01-10
- Certified
- 2024-01-10
Frequently asked questions
- What is Timothy Wassenaar's NPI number?
- Timothy Wassenaar's National Provider Identifier (NPI) is 1518928993, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Timothy Wassenaar's specialty?
- Timothy Wassenaar is listed in the NPPES registry with a primary specialty of Hematology & Oncology Physician (Allopathic & Osteopathic Physicians).
- Where is Timothy Wassenaar located?
- Timothy Wassenaar's practice location on file with NPPES is N16w24131 Riverwood Dr, Waukesha, WI 53188-1106.
- What is Timothy Wassenaar's phone number?
- The practice phone number listed in the NPPES registry for Timothy Wassenaar is (262) 696-5690.
- Does Timothy Wassenaar accept Medicare?
- Timothy Wassenaar is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Timothy Wassenaar's NPI active?
- Yes — Timothy Wassenaar's NPI (1518928993) is active in the NPPES registry as of the last update on 2024-01-10.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.