G0659 HCPCS code: Drug test(s), definitive, utilizing drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including but not limited to gc/ms (any type, single or tandem) and lc/ms (any type, single or tandem), excluding immunoassays (e.g., ia, eia, elisa, emit, fpia) and enzymatic methods (e.g., alcohol dehydrogenase), performed without method or drug-specific calibration, without matrix-matched quality control material, or without use of stable isotope or other universally recognized internal standard(s) for each drug, drug metabolite or drug class per specimen; qualitative or quantitative, all sources, includes specimen validity testing, per day, any number of drug classes
G0659 is the HCPCS Level II code for drug test(s), definitive, utilizing drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including but not limited to gc/ms (any type, single or tandem) and lc/ms (any type, single or tandem), excluding immunoassays (e.g., ia, eia, elisa, emit, fpia) and enzymatic methods (e.g., alcohol dehydrogenase), performed without method or drug-specific calibration, without matrix-matched quality control material, or without use of stable isotope or other universally recognized internal standard(s) for each drug, drug metabolite or drug class per specimen; qualitative or quantitative, all sources, includes specimen validity testing, per day, any number of drug classes. In 2024 Medicare paid an average of $51.82 per service for G0659 across 509 services. Its Medicare coverage code is C (Carrier judgment): Coverage is decided by the Medicare contractor (MAC) case by case. The NCCI unit limit is 1 per day on outpatient hospital claims. Medicare volume fell 16% from 2022 to 2024 (609 to 509 services). In 2024, about 31 clinicians billed Medicare for G0659 for 225 beneficiaries; New York, Oklahoma, Arkansas accounted for 83% of services.
Code details
| Field | Value |
|---|---|
| Section | G codes — Procedures and professional services (temporary) |
| Coverage code | C — Carrier judgment |
| Pricing indicator | 21 — Priced on the Clinical Laboratory Fee Schedule |
| BETOS category | T1H |
| Added | 2017-01-01 |
| Last action effective | 2017-01-01 |
Who bills G0659 (2024)
| Measure | Value |
|---|---|
| Clinicians billing (by place of service) | 31 |
| Medicare beneficiaries | 225 |
| States with claims | 6 |
| Share of services in top 3 states (New York, Oklahoma, Arkansas) | 83% |
Counts only. Supplier and clinician names, contact lists and state-by-state detail are in Caduvo.
Medicare utilization for G0659, 2022–2024
| Year | Services | Beneficiaries | Avg. allowed | Avg. paid |
|---|---|---|---|---|
| 2022 | 609 | 197 | $52.59 | $52.59 |
| 2023 | 674 | 303 | $50.99 | $50.99 |
| 2024 | 509 | 225 | $51.82 | $51.82 |
States with the most G0659 services (2024)
| State | Services | Avg. paid |
|---|---|---|
| New York | 266 | $59.85 |
| Oklahoma | 103 | $39.20 |
| Arkansas | 49 | $60.90 |
| New Mexico | 45 | $24.33 |
| North Carolina | 19 | $60.90 |
NCCI unit limits (MUE)
| Claim type | Max units per day | Rationale |
|---|---|---|
| outpatient hospital claims | 1 | Code Descriptor / CPT Instruction |
| practitioner claims | 1 | Code Descriptor / CPT Instruction |
Medicare policy articles for this code
- A54799: Billing and Coding: Urine Drug Testing (Palmetto GBA (MAC - Part A, MAC - Part B))
- A55001: Billing and Coding: Urine Drug Testing (Noridian Healthcare Solutions, LLC (MAC - Part A, MAC - Part B))
- A56645: Billing and Coding: Controlled Substance Monitoring and Drugs of Abuse Testing (Novitas Solutions, Inc. (MAC - Part A, MAC - Part B))
- A56818: Billing and Coding: Urine Drug Testing (CGS Administrators, LLC (MAC - Part A, MAC - Part B))
- A56915: Billing and Coding: Urine Drug Testing (WPS Insurance Corporation (MAC - Part A, MAC - Part B))
- A57077: Billing and Coding: Controlled Substance Monitoring and Drugs of Abuse Testing (First Coast Service Options, Inc. (MAC - Part A, MAC - Part B))
- A59416: Billing and Coding: Urine Drug Testing (Wellpoint Federal (MAC - Part A, MAC - Part B))
Covered diagnoses (1,451 ICD-10-CM codes)
The diagnoses most often listed as covered in the policy articles above:
| ICD-10-CM | Diagnosis | Articles listing it |
|---|---|---|
| E87.21 | Acute metabolic acidosis | 7 |
| E87.22 | Chronic metabolic acidosis | 7 |
| E87.29 | Other acidosis | 7 |
| F11.20 | Opioid dependence, uncomplicated | 7 |
| F11.220 | Opioid dependence with intoxication, uncomplicated | 7 |
| F11.221 | Opioid dependence with intoxication delirium | 7 |
| F11.222 | Opioid dependence with intoxication with perceptual disturbance | 7 |
| F11.229 | Opioid dependence with intoxication, unspecified | 7 |
| F11.23 | Opioid dependence with withdrawal | 7 |
| F11.24 | Opioid dependence with opioid-induced mood disorder | 7 |
Showing 10 of 1,451. The full list, non-covered diagnoses and CSV export are in Caduvo.
What changed for G0659
- 2017-01-01: G0659 added to HCPCS Level II
- Next scheduled CMS quarterly update (HCPCS and DMEPOS fee schedule): 2027-01-01
Frequently asked questions
What is HCPCS code G0659?
G0659 is the HCPCS Level II code for drug test(s), definitive, utilizing drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including but not limited to gc/ms (any type, single or tandem) and lc/ms (any type, single or tandem), excluding immunoassays (e.g., ia, eia, elisa, emit, fpia) and enzymatic methods (e.g., alcohol dehydrogenase), performed without method or drug-specific calibration, without matrix-matched quality control material, or without use of stable isotope or other universally recognized internal standard(s) for each drug, drug metabolite or drug class per specimen; qualitative or quantitative, all sources, includes specimen validity testing, per day, any number of drug classes. Short descriptor: "Drug test def simple all cl".
How much does Medicare pay for G0659?
In 2024, the average Medicare payment was $51.82 per service (average allowed $51.82).
Does Medicare cover G0659?
Coverage code C — Carrier judgment. Coverage is decided by the Medicare contractor (MAC) case by case.
Which diagnoses support coverage for G0659?
Medicare policy articles that cite G0659 list 1,451 covered ICD-10-CM diagnosis codes across 7 articles. The most cited include E87.21 (Acute metabolic acidosis), E87.22 (Chronic metabolic acidosis), E87.29 (Other acidosis). A listed diagnosis is necessary but not sufficient; the policy's other criteria still apply.
How many units of G0659 can be billed per day?
1 on outpatient hospital claims; 1 on practitioner claims (NCCI medically unlikely edits).
Building a device that would bill under a code like this? Caduvo matches a device description to HCPCS/CPT codes, Medicare coverage and payment, and the FDA pathway in one report.
Next steps
- Run a reimbursement report for a device billed under G0659
- Watch G0659 for fee, coverage and descriptor changes
- Build a full Medicare revenue model for G0659
Sources: CMS HCPCS Level II release October 2025; CMS DMEPOS fee schedule; CMS NCCI MUE tables; CMS Medicare utilization (physician and DME supplier files); CMS Medicare Coverage Database articles. Fees are Medicare allowables, not commercial rates. Not billing or legal advice.