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NPI 1992816169 · Tamuning, GU · Emergency Medicine Physician
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Selwyn Mahon is a emergency medicine physician provider located in Tamuning, Guam. This profile covers 4 Medicare and 3 Medicaid CPT/HCPCS procedure codes, with claims volume, average reimbursement, and total revenue by code, benchmarked against other providers billing the same services.
Provider details (source: NPPES NPI Registry)
| Field | Value |
|---|---|
| Entity Type | Individual |
| Organization | Selwyn Mahon |
| Address | 850 Gov. Carlos Camacho Road |
| City | Tamuning |
| State | GU |
| ZIP | 96913 |
| Taxonomy | Emergency Medicine Physician |
| NPI Enumerated | August 31, 2006 |
Lifetime revenue by payer source (source: CMS Medicare & Medicaid claims data)
| Payer Source | Total Paid |
|---|---|
| Medicaid | $61K |
| Medicare | $15.3K |
Billing is concentrated in emergency department evaluation-and-management services: the provider’s top codes are 99285, 99284 and 99283, which by description are high-, moderate- and low-complexity emergency department E/M visits. This code mix aligns with the listed taxonomy (Emergency Medicine Physician) and indicates the practice is functioning primarily as an ED clinician handling acute presentations rather than delivering outpatient longitudinal care.
Revenue is highly concentrated in a very small set of ED visit codes: the precomputed top 3 Medicare codes account for 99.6% of the provider's total Medicare revenue, and the top 3 Medicaid codes account for 100.0% of total Medicaid revenue. That concentration implies operational exposure to volume and reimbursement changes affecting those specific E/M codes.
The provider’s payer mix is skewed toward Medicaid: total Medicaid revenue is $61K compared with total Medicare revenue of $15.3K, so Medicaid is the larger single source of billed public-payer revenue on file. This pattern makes in-state Medicaid reimbursement and access policies particularly important to the provider’s overall public-payer performance.
National competitive standing on Medicare E/M is modest. For 99285 the provider ranks #41501 of 61347 providers nationally (32th percentile; typical, unremarkable volume for this code), for 99284 the provider ranks #30289 of 64306 providers nationally (52th percentile; typical, unremarkable volume for this code), and for 99283 the provider ranks #25665 of 31069 providers nationally (12th percentile; typical, unremarkable volume for this code); these placements indicate routine, not leading, Medicare activity on those codes.
State-level competitive standing on Medicaid is limited: for 99285 the provider ranks #4 of 5 in-state (25th percentile; typical, unremarkable volume), for 99284 the provider ranks #4 of 5 in-state (25th percentile; typical, unremarkable volume), and for 99283 the provider ranks #5 of 5 in-state (0th percentile; typical, unremarkable volume). Those in-state ranks position this provider as a modest participant in the local Medicaid ED billing landscape rather than a dominant in-state biller.
Medicare top-code volumes and dollars are small in absolute terms: 99285 had 60 claims at $140 avg paid/claim for $8.4K revenue (55.0% of this provider's total Medicare revenue), 99284 had 63 claims at $96 avg paid/claim for $6K revenue (39.6% of this provider's total Medicare revenue), and 99283 had 13 claims at $58 avg paid/claim for $754 revenue (4.9% of this provider's total Medicare revenue). These counts and payments reflect limited Medicare throughput concentrated in a few high-acuity ED visits.
Medicaid volumes are substantially higher and similarly concentrated in ED visit codes: 99285 shows 312 claims at $109 avg paid/claim for $34K revenue (55.7% of this provider's total Medicaid revenue), 99284 shows 349 claims at $62 avg paid/claim for $21.6K revenue (35.4% of this provider's total Medicaid revenue), and 99283 shows 142 claims at $38 avg paid/claim for $5.4K revenue (8.8% of this provider's total Medicaid revenue). The Medicaid billing profile indicates higher ED patient volume billed to state programs, but ranks suggest typical, unremarkable volumes among in-state peers.
The provider has a long enrollment history that may reflect sustained local presence: the NPI was enumerated on 2006-08-31 (~20 years ago). Ancillary services are negligible on Medicare filings — for example, 93010 appears with 11 claims at $6 avg paid/claim for $66 revenue (0.4% of this provider's total Medicare revenue) — underscoring that ED E/M dominates both clinical and billing activity.
Medicare revenue breakdown by CPT/HCPCS procedure code.
View: Bar Chart1 / 2
The CPT/HCPCS codes generating the most Medicare revenue for this provider.
4 rows
| CPT/HCPCS Code | Description | Claims | Avg Paid | Revenue |
|---|---|---|---|---|
| 99285 | The provider sees a patient for an emergency department visit involving evaluation and management (E/M). The visit involves a high level of medical decision making. | 60 | $140 | $8.4K |
| 99284 | The provider sees a patient for an emergency department visit involving evaluation and management (E/M). The visit involves a moderate level of medical decision making. | 60 | $100 | $6K |
| 99283 | The provider sees a patient for an emergency department visit involving evaluation and management (E/M). The visit involves a low level of medical decision making. | 10 | $60 | $750 |
| 93010 | The provider interprets and reports on the results of a routine 12–lead (or more) electrocardiogram. | 10 | $10 | $70 |
How this provider's Medicare billing volume and revenue compare to other providers nationally and within its state, across 4 CPT/HCPCS codes.
Medicaid revenue breakdown by year and by CPT/HCPCS procedure code, including monthly billing trends and the top codes driving revenue.
View: By Year1 / 3
Every CPT/HCPCS code this provider has billed to Medicaid, with claims volume, average payment, and total revenue.
3 rows
| CPT/HCPCS Code | Description | Claims | Avg Paid | Revenue |
|---|---|---|---|---|
| 99285 | The provider sees a patient for an emergency department visit involving evaluation and management (E/M). The visit involves a high level of medical decision making. | 310 | $110 | $34K |
| 99284 | The provider sees a patient for an emergency department visit involving evaluation and management (E/M). The visit involves a moderate level of medical decision making. | 350 | $60 | $21.6K |
| 99283 | The provider sees a patient for an emergency department visit involving evaluation and management (E/M). The visit involves a low level of medical decision making. | 140 | $40 | $5.4K |
How this provider's Medicaid billing volume and revenue compare to other Guam providers billing the same CPT/HCPCS codes.
Full comparison — all codes billed, vs. Guam median
3 rows
| CPT/HCPCS Code | Description | Rank | Provider Count | Median Claims | Avg Paid | Average Revenue |
|---|---|---|---|---|---|---|
| 99283 | The provider sees a patient for an emergency department visit involving evaluation and management (E/M). The visit involves a low level of medical decision making. | 5 | 10 | 1,880 | $410 | $2M |
| 99284 | The provider sees a patient for an emergency department visit involving evaluation and management (E/M). The visit involves a moderate level of medical decision making. | 4 | 10 | 3,240 | $290 | $1.3M |
| 99285 | The provider sees a patient for an emergency department visit involving evaluation and management (E/M). The visit involves a high level of medical decision making. | 4 | 10 | 1,010 | $140 | $191.9K |
Other providers in the same ZIP code as Selwyn Mahon, ranked by combined Medicare and Medicaid revenue.
| Provider | State | Taxonomy | Medicare Revenue | Medicaid Revenue |
|---|---|---|---|---|
| Thomas Lee | GU | Dentist | $0 | $10.9M |
| Guam Memorial Hospital | GU | General Acute Care Hospital | $0 | $3.5M |
| Rsa - Tumon, LLC | GU | End-Stage Renal Disease (ESRD) Treatment Clinic/Center | $0 | $2.9M |
| Robert Yang | GU | Dentist | $0 | $2.4M |
| Antonio Garcia | GU | Pediatrics Physician | $0 | $2.2M |
| Ma Gladys Linsangan | GU | Pediatrics Physician | $0 | $2.2M |
| Ari Katerelos | GU | Radiation Oncology Physician | $2.1M | $0 |
| Guam X-ray | GU | Vascular & Interventional Radiology Physician | $0 | $2.1M |
| Sarah Clegg | GU | General Practice Dentistry | $0 | $1.7M |
| Peter Kh Go | GU | Surgery Physician | $152.8K | $1.5M |
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