G0659 – 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

HCPCS Level II code · G codes: Procedures / Professional Services (Temporary)

Active code Carrier judgment

HCPCS codeG0659
Long description
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 description
Drug test def simple all cl
Pricing indicator
21 Clinical Lab Fee Schedule – national limitation amount
Medicare coverage
C Carrier judgment – coverage decided by the Medicare contractor
BETOS category
T1H Lab tests - other (Non-Medicare fee schedule)
Added
January 1, 2017
Last change
January 1, 2017 – No change

Frequently asked questions

What is HCPCS code G0659?

G0659 is a 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.

Does Medicare cover G0659?

The HCPCS file lists coverage code C: Carrier judgment – coverage decided by the Medicare contractor. Coverage and payment also depend on local coverage determinations and the patient’s plan.

Nearby G codes

Source: CMS HCPCS Level II quarterly file, October 2026. Reference only – check payer policy before billing.