How should a device rep approach an anesthesiology territory when the Anesthesiology query hits the 200-record cap in most markets?

For markets where the city-based Anesthesiology query hits the 200-record cap (Memphis, Nashville, all major metros), the full call list requires multiple queries: query by ZIP code in 10–15 mile increments, or by hospital ZIP codes, to recover the complete market without missing providers whose address falls outside the main city name. For smaller territories (Wyoming's 194, Vermont's 200-cap is just barely at the cap), the statewide query without a city filter may recover the full list in one request. getdork handles this by applying Haversine radius filtering across all ZIP codes, so a single radius query returns the complete territory.

Find Anesthesiologists by Zip Code — NPI Registry Guide

Q: Why does 'Anesthesia' return zero NPI results?

The NPI API performs exact or prefix matching on taxonomy_description. 'Anesthesia' does not match the NUCC taxonomy string for physician anesthesiologists, which is 'Anesthesiology' (207L00000X). The word 'Anesthesia' describes the clinical technique or drug class — not the physician specialty designation. This is the same rule as other specialties: 'Cardiology' returns zero (use 'Cardiovascular Disease'), 'Neuroscience' returns zero (use 'Neurology'). The formal specialty noun form is what the NUCC uses.

Q: What happens when you query 'Anesthesiologist' instead of 'Anesthesiology'?

The 'Anesthesiologist' query prefix-matches on 'Anesthesiologist Assistant' — a non-physician clinical role (typically a master's-level healthcare professional who works under physician supervision). Both 'Anesthesiologist' and 'Anesthesiologist Assistant' share the prefix. The national 'Anesthesiologist' query returned 200+ (capped) — a mix of MD anesthesiologists and non-physician Anesthesiologist Assistants. Using 'Anesthesiology' avoids this ambiguity: it returns the physician specialty group exclusively.

Q: What is the difference between an Anesthesiologist, an Anesthesiologist Assistant, and a CRNA in the NPI registry?

Anesthesiologist (207L00000X): MD or DO physician, completed anesthesiology residency, attends surgery independently, physician prescriber. Anesthesiologist Assistant: non-physician, master's-level, works under physician supervision, 200+ nationally (capped). CRNA — Nurse Anesthetist, Certified Registered: non-physician advanced practice nurse, 200+ nationally (capped), separate from MDs. In the Memphis Anesthesiology query data (200 records, capped), the credential breakdown showed: MD: 90, M.D.: 50, (no credential/NPI-2 orgs): 43, CRNA: 4, DO: 4 — the CRNA and DO credentials that appeared in the Anesthesiology query are providers who listed Anesthesiology as a secondary taxonomy or share a group address.

Q: How do anesthesiology subspecialties appear in the Anesthesiology NPI query?

The 'Anesthesiology' query prefix-matches all anesthesiology subcodes. Memphis raw data (200 records): 158 primary Anesthesiology (207L00000X), 13 Anesthesiology, Pain Medicine, 7 Anesthesiology, Pediatric Anesthesiology, 2 Anesthesiology, Addiction Medicine, 7 Nurse Anesthetist, Certified Registered (appeared in query page), 3 Internal Medicine/Emergency Medicine records (address-matched). For a rep targeting pure attending anesthesiologists — not pain subspecialists or pediatric subspecialists — filter on primary taxonomy code 207L00000X specifically.

Published 2026-06-13 · Data queried from CMS NPI Registry v2.1 · getdork

Methodology: All counts queried live from CMS NPI Registry API v2.1 on 2026-06-13 using taxonomy_description=Anesthesiology. No auth required. result_count=200 means page cap hit; true total is higher. Raw data: npi-counts-anesthesiology.json · Memphis raw · Vermont raw · Script: npi-counts-anesthesiology.ps1

The short answer: Use taxonomy_description=Anesthesiology (NUCC 207L00000X) for MD physician anesthesiologists. "Anesthesia" returns zero. "Anesthesiologist" prefix-matches on "Anesthesiologist Assistant" — a non-physician role — contaminating the results. CRNAs (Nurse Anesthetist, Certified Registered) are a separate non-physician code with 200+ national records.

Critical gotcha — empirically verified 2026-06-13: taxonomy_description=Anesthesia → 0 results
taxonomy_description=Anesthesiologist → 200+ (capped) — but includes Anesthesiologist Assistants (non-physician, 200+ nationally on their own)
taxonomy_description=Nurse+Anesthetist%2C+Certified+Registered (CRNA) → 200+ (separate non-physician code)

A rep targeting MD anesthesiologists specifically must use Anesthesiology (207L00000X) and then filter the raw data by credential (MD/DO) or primary taxonomy code to exclude Anesthesiologist Assistants and CRNAs that may appear via prefix-match or address overlap. Memphis analysis: of 200 capped records, 158 had primary Anesthesiology (207L00000X), 140 had MD or M.D. credentials — the clearest signal of the physician population.

Anesthesiology records by market — 2026-06-13

Market	Records returned	Notes
New York, NY	200+	Capped — true total far exceeds 200
Chicago, IL	200+	Capped
Los Angeles, CA	200+	Capped
Houston, TX	200+	Capped
Phoenix, AZ	200+	Capped
Nashville, TN	200+	Capped
Memphis, TN	200+	Capped — see drill-down below
Vermont (statewide)	200+	Capped — statewide total exceeds 200
Wyoming (statewide)	194	Complete statewide count — near the cap

Source: npi-counts-anesthesiology.json, queried 2026-06-13. Anesthesiology is one of the densest hospital-based specialties — nearly all markets cap at 200.

Memphis drill-down — Anesthesiology, 2026-06-13 (n=200, capped)
Entity type: 164 NPI-1 (individual providers) · 36 NPI-2 (organizations: anesthesia groups, hospital-based anesthesia departments)
Primary taxonomy breakdown (first 200 records):
• 158 records: 207L00000X — Anesthesiology (MD/DO attending anesthesiologists)
• 13 records: Anesthesiology, Pain Medicine (subspecialty)
• 7 records: Anesthesiology, Pediatric Anesthesiology
• 7 records: Nurse Anesthetist, Certified Registered (CRNAs — appeared in query page)
• 2 records: Anesthesiology, Addiction Medicine
• 13 records: Internal Medicine, Emergency Medicine, other (address-matched overlap)
Credential breakdown: MD: 90 · M.D.: 50 · (none/NPI-2 orgs): 43 · DO: 4 · CRNA: 4 · others: 9

For a device rep targeting MD anesthesiologists specifically: filter on primary taxonomy 207L00000X and credential containing MD/DO. The 158 Anesthesiology-primary records, cross-referenced with MD/M.D./DO credentials, yield the physician attending anesthesiologist call list.

Wyoming (n=194, complete): A near-complete statewide anesthesiology count. At 194, this is large enough to segment by hospital system or region for territory planning.

Anesthesia provider types in the NPI registry

Provider type	NUCC code	Credential	National count	Physician?
`Anesthesiology`	207L00000X	MD, DO	200+ (capped)	Yes — MD/DO
`Anesthesiologist Assistant`	(separate)	AA-C, CAA	200+ (capped)	No — non-physician, master's-level
`Nurse Anesthetist, Certified Registered`	(separate)	CRNA	200+ (capped)	No — advanced practice nurse
`Anesthesia`	N/A	—	0 results	—

Verified live 2026-06-13. Source: npi-counts-anesthesiology.json.

How to build an anesthesiologist call list

Query Anesthesiology — not Anesthesiologist or Anesthesia

https://npiregistry.cms.hhs.gov/api/?version=2.1
  &taxonomy_description=Anesthesiology
  &city=Memphis&state=TN&limit=200

Returns 200 capped for Memphis. In the raw data, 158 of 200 records had primary taxonomy Anesthesiology (207L00000X). Filter on MD/M.D./DO credential for the physician call list. Do not use "Anesthesiologist" — it prefix-matches on Anesthesiologist Assistant, a separate non-physician role.

For pain-focused products, also sample Anesthesiology, Pain Medicine

13 of the 200 Memphis records had primary taxonomy Anesthesiology, Pain Medicine — anesthesiologists who transitioned to or also practice chronic pain management. The pain medicine guide covers the full Pain Medicine taxonomy breakdown, which draws from multiple parent specialties. For a product targeting OR-based anesthesiologists specifically, filter to primary taxonomy 207L00000X and exclude the pain subspecialty records.

Handle the cap with radius-based ZIP queries in dense markets

Every major market hits the 200-record cap. To recover the complete city-level call list, query by ZIP code in 10–15 mile increments, or pull by hospital ZIP codes, to capture all anesthesia providers across the metro. getdork's radius search does this automatically — a 25-mile radius query returns the full territory without cap-induced gaps.

Search anesthesiologists by ZIP — free
getdork queries Anesthesiology (not the ambiguous "Anesthesiologist"), handles the 200-record cap with radius-based ZIP filtering, and exports a CRM-ready CSV.

Search anesthesiologists in your territory →

Radius guidance for anesthesiology territories

Anesthesiologists practice exclusively at hospitals, surgery centers, and procedural facilities. Unlike primary care or outpatient specialties, there are no solo-practice anesthesiologists. They are found wherever there is an operating room — which in most mid-size cities means 5–10 hospital and ASC sites within 25 miles.

All major metros (NYC, Chicago, LA, Houston, Phoenix, Nashville, Memphis — all 200+ capped): 15–25 miles captures most OR sites; use ZIP-by-ZIP or radius search to recover the full market beyond the cap
Mid-size metros not yet capped: 25 miles covers the major hospital and ASC cluster
Wyoming (194 statewide): the near-complete statewide count is small enough to segment by hospital system; no radius math needed

Frequently asked questions

Why does "Anesthesia" return zero NPI results?

"Anesthesia" refers to the clinical technique and drug class — not the physician specialty designation. The NUCC taxonomy for physician anesthesiologists is "Anesthesiology" (207L00000X). The API matches on taxonomy_description; "Anesthesia" matches no NUCC entry and returns zero. This mirrors other fields where the technique name and the specialty noun diverge: "Surgery" returns general surgeons (it is the NUCC string), but "Anesthesia" does not return anesthesiologists (the NUCC string is the full specialty name, "Anesthesiology").

What happens when you query "Anesthesiologist" instead of "Anesthesiology"?

"Anesthesiologist" prefix-matches on "Anesthesiologist Assistant" — a non-physician master's-level role that works under physician supervision. The national "Anesthesiologist" query returned 200+ (capped) — a mix of MD anesthesiologists and non-physician AAs. "Anesthesiology" returns the physician specialty group exclusively. The distinction matters for a pharma or device rep targeting physician prescribers and decision-makers: AAs do not have independent prescribing authority.

What is the difference between an Anesthesiologist, an Anesthesiologist Assistant, and a CRNA?

Anesthesiologist (207L00000X): MD or DO, completed 4-year anesthesiology residency, physician prescriber. Anesthesiologist Assistant: non-physician, master's-level, works under physician supervision, separate NUCC code (200+ nationally). CRNA: Nurse Anesthetist, Certified Registered — advanced practice nurse, separate NUCC code (200+ nationally). In the Memphis Anesthesiology query data (200 records): MD: 90, M.D.: 50, CRNA: 4 appeared in the dataset, DO: 4. The 4 CRNAs appeared because their group practice addresses overlapped with the physician query results.

How do anesthesiology subspecialties appear in the Anesthesiology query?

The "Anesthesiology" query prefix-matches all subcodes. Memphis raw data (200 records): 158 primary Anesthesiology (207L00000X), 13 Anesthesiology, Pain Medicine, 7 Anesthesiology, Pediatric Anesthesiology, 2 Anesthesiology, Addiction Medicine. For a rep targeting pure OR-based attending anesthesiologists — not pain subspecialists — filter on primary taxonomy code 207L00000X. For a pain product, the pain subspecialty records (13 in Memphis) are also relevant, but the pain medicine guide covers that call list in detail.

Why is the Memphis anesthesiology count capped at 200 while Wyoming returned 194?

Memphis returned 200 (capped — true total exceeds 200); Wyoming statewide returned 194 (the complete statewide count). Wyoming's 194 is the actual complete number. Memphis's 200 is the API's per-page cap — the real Memphis total is higher. Anesthesiology is one of the densest hospital-based specialties: every operating room requires coverage. Memphis has multiple large hospital systems plus a medical school with an active anesthesiology department — well over 200 anesthesia providers within city limits.

How should a device rep handle the anesthesiology market when the query caps at 200 in nearly every city?

The 200-record cap affects nearly every major anesthesiology market. To recover the full territory: query by ZIP code in overlapping radius increments (e.g., 10-mile radius from each hospital campus ZIP), deduplicate on NPI number, and combine. This is exactly what getdork's radius search handles automatically — a 25-mile radius from a central ZIP runs Haversine filtering across all ZIP codes in range and returns the complete call list without manually managing the 200-cap pagination.

Methodology

All data queried live from CMS NPI Registry API v2.1 on 2026-06-13. Gotcha queries confirmed: Anesthesia returned zero results; Anesthesiologist returned 200+ (capped, mixed with Anesthesiologist Assistants); Anesthesiologist+Assistant returned 200+ (non-physician population, separate code); Nurse+Anesthetist%2C+Certified+Registered returned 200+ (CRNA, separate code). All confirmed in npi-counts-anesthesiology.json. Memphis raw data breakdown derived from npi-anesthesiology-memphis-tn-raw.json.

Related guides

How to search the NPI registry
What is an NPI number?
How to find physicians by specialty and state
Find pain management doctors by zip code — includes Anesthesiology, Pain Medicine subspecialty
Find general surgeons by zip code — the OR call list that shares anesthesia coverage