Mark Slack, MD
NPI 1679508618 · Anesthesiology Physician · Manassas, VA
Enrolled with Medicare as Practitioner - Anesthesiology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Slack, MD is a Anesthesiology Physician provider in Manassas, VA (NPI 1679508618).
Provider details
- NPI number
- 1679508618
- Entity type
- Individual
- Primary specialty
- Anesthesiology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 0101044713 (VA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 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
47 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) |
|---|---|---|
| Anesthesia for Lens Surgery00142 | 16 | $107 |
| Anesthesia for Other Procedure on Large Bowel Using an Endoscope00811 | 16 | $119 |
| Anesthesia for Other Procedure on Esophagus, Stomach, Or Upper Small Bowel Using an Endoscope00731 | 15 | $131 |
Typical Medicare-allowed amounts for these services range $107–$131 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-07-11
- Last updated
- 2017-02-15
Frequently asked questions
- What is Mark Slack's NPI number?
- Mark Slack's National Provider Identifier (NPI) is 1679508618, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Slack's specialty?
- Mark Slack is listed in the NPPES registry with a primary specialty of Anesthesiology Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Slack located?
- Mark Slack's practice location on file with NPPES is 8700 Sudley Rd, Manassas, VA 20110-4418.
- What is Mark Slack's phone number?
- The practice phone number listed in the NPPES registry for Mark Slack is (703) 369-8000.
- Does Mark Slack accept Medicare?
- Mark Slack is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Slack's NPI active?
- Yes — Mark Slack's NPI (1679508618) is active in the NPPES registry as of the last update on 2017-02-15.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.