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HCPCS G0166 · Level II · G code

G0166: External counterpulsation, per treatment session, HCPCS Level II G code

Compiled from CMS files by the QuickIntell RCM Editorial Team · Data effective · Method: reference methodology · Report a data correction

Data currency: HCPCS Level II file: October 2026 (effective October 1, 2026); PFS relative value file: RVU26D, released August 26, 2026 (effective October 1, 2026); NCCI MUE tables: 2026 Q4 (effective October 1, 2026); NCCI PTP edits: v323r0 (2026 Q4) (effective October 1, 2026); OPPS Addendum B: October 2026 (effective October 1, 2026). Next CMS release: January 1, 2027 (quarterly update) for the HCPCS Level II file and NCCI MUE tables and NCCI PTP edits and OPPS Addendum B; RVU27A with the CY2027 PFS final rule, effective January 1, 2027 for the PFS relative value file.

Key facts for G0166

Medicare payment
$102.87
PFS non-facility, national
Coverage code
D
special coverage instructions apply
Practitioner MUE
2
MAI 3
OPPS status
SI Q1
STV-Packaged Codes
NCCI PTP pairs
19
16 hospital outpatient
LCDs and articles
0 / 0

TL;DR

G0166 is a Level II code from the G section (procedures and professional services, temporary), in use since 2000: "External counterpulsation, per treatment session". National PFS payment for G0166 is $102.87 in an office and no facility amount in a facility (October 2026), built from 0.00 work, 3.04 practice-expense and 0.04 malpractice RVUs at $33.4009 per RVU. Qualifying APM participants get $103.39 at $33.5675. CMS caps G0166 at practitioner 2 (MAI 3, Nature of Service/Procedure); hospital outpatient 2 (MAI 3, Nature of Service/Procedure) units per day in the 2026 Q4 MUE tables. In the NCCI PTP files v323r0 G0166 appears in 0 practitioner pairs as column 2 and 19 as column 1, and in 0 hospital outpatient pairs as column 2 and 16 as column 1. No current LCD or billing article lists G0166; its HCPCS coverage code is D (special coverage instructions apply). HCPCS record: BETOS P6C (minor procedures - other (Medicare fee schedule)); pricing indicator 11; type of service 1 (medical care). Nearby codes: G0168, G0160, G0159, G0158.

G0166 descriptor and code status

The October 2026 HCPCS Level II file describes G0166 as “External counterpulsation, per treatment session”. It sits in the G section (procedures and professional services, temporary), listed with the other G codes. Although searches often call it the "G0166 CPT code", G0166 is a HCPCS Level II code maintained by CMS, not an AMA CPT code; both go in the same procedure-code field on the claim.

HCPCS file attributes of G0166
FieldValue
Short descriptorExtrnl counterpulse, per tx
Added to HCPCS2000-01-01
Last actionN (no maintenance), effective 2000-01-01
Coverage codeD: special coverage instructions apply
Pricing indicator11: physician fee schedule, priced with national RVUs
BETOS categoryP6C: minor procedures - other (Medicare fee schedule)
Type of service1: medical care

Medicare payment for G0166

National PFS payment for G0166 is $102.87 in an office and no facility amount in a facility (October 2026), built from 0.00 work, 3.04 practice-expense and 0.04 malpractice RVUs at $33.4009 per RVU. Qualifying APM participants get $103.39 at $33.5675. The amounts below are national figures from the October 2026 CMS files; the contractor applies the locality, rural or state adjustment and the beneficiary's cost sharing.

Physician fee schedule (RVU26D)

Status A: active: paid separately under the physician fee schedule when covered. Global period XXX (global surgery concept does not apply); PC/TC indicator 5 (incident-to service).

PFS relative values and national payment for G0166
ComponentNon-facilityFacility
Work RVU0.000.00
Practice expense RVU3.04NA
Malpractice RVU0.040.04
Total RVUs3.08NA
National payment (CF $33.4009)$102.87n/a
Qualifying APM participant (CF $33.5675)$103.39n/a
  • Multiple procedures (modifier 51): multiple-procedure concept does not apply
  • Bilateral (modifier 50): bilateral concept does not apply
  • Assistant at surgery: assistant-at-surgery concept does not apply; co-surgeons: co-surgery concept does not apply; team surgery: team-surgery concept does not apply
  • Physician supervision of diagnostic procedures: supervision concept does not apply

Hospital outpatient (OPPS Addendum B)

Status indicator Q1 (STV-Packaged Codes), APC 5734 (Level 4 Minor Procedures), national unadjusted payment $135.93 with a minimum unadjusted copayment of $27.19.

Medically Unlikely Edits for G0166

CMS caps G0166 at practitioner 2 (MAI 3, Nature of Service/Procedure); hospital outpatient 2 (MAI 3, Nature of Service/Procedure) units per day in the 2026 Q4 MUE tables. The practitioner MUE is a date-of-service clinical edit: units above the limit deny but can be paid on appeal with documentation.

MUE values for G0166 by setting
SettingMUE (units/DOS)MAICMS rationale
Practitioner services23 Date of Service Edit: ClinicalNature of Service/Procedure
Facility outpatient hospital23 Date of Service Edit: ClinicalNature of Service/Procedure

The MUE lookup for G0166 shows every setting next to any other code on the same claim.

NCCI edits and add-on rules

In the practitioner PTP file v323r0, G0166 is the column-2 (bundled) code in 0 active pairs and the column-1 code in 19 (47% modifier-allowed); 75 earlier pairs have been deleted.

Column-2 codes bundled into G0166 (practitioner)
Column-2 codePairs
0903T (CPT; descriptor licensed by AMA)1
0904T (CPT; descriptor licensed by AMA)1
0905T (CPT; descriptor licensed by AMA)1
36591 (CPT; descriptor licensed by AMA)1
36592 (CPT; descriptor licensed by AMA)1
92971 (CPT; descriptor licensed by AMA)1
93000 (CPT; descriptor licensed by AMA)1
93005 (CPT; descriptor licensed by AMA)1

In the hospital outpatient PTP file v323r0, G0166 is the column-2 (bundled) code in 0 active pairs and the column-1 code in 16 (56% modifier-allowed); 9 earlier pairs have been deleted.

Column-2 codes bundled into G0166 (hospital outpatient)
Column-2 codePairs
0903T (CPT; descriptor licensed by AMA)1
0904T (CPT; descriptor licensed by AMA)1
0905T (CPT; descriptor licensed by AMA)1
92971 (CPT; descriptor licensed by AMA)1
93000 (CPT; descriptor licensed by AMA)1
93005 (CPT; descriptor licensed by AMA)1
93010 (CPT; descriptor licensed by AMA)1
93040 (CPT; descriptor licensed by AMA)1

G0166 is neither an add-on code nor a designated primary code in the 2026 Q4 NCCI add-on edit file.

Pair counts show exposure, not the answer for one claim. Check G0166 against a second code to see whether the pair bundles and whether a modifier can separate the services.

Medicare coverage policies for G0166

No current LCD or billing and coding article lists G0166. The HCPCS coverage code D means special coverage instructions apply, and any National Coverage Determination for the service still applies.

Denials to expect on G0166

CARC 50 · N115

the service is not reasonable and necessary for the diagnosis on the claim

CARC 151 · N362

units of G0166 exceed the practitioner MUE of 2 per date of service

CARC 4

the modifier reported is inconsistent with the code

CARC 16

the claim lacks information needed to adjudicate the line, such as an order, NPI or required modifier

Where QuickIntell fits for G0166 claims

QuickCode supports qualified coder review of units, modifiers and NCCI pairs for G0166 before the claim leaves, and QuickRCM carries claim readiness and the denial follow-up when an edit or coverage policy is missed.

See QuickCode for coder reviewSee QuickRCM for denial follow-upBook a meeting

Frequently asked questions: HCPCS G0166

What does HCPCS code G0166 describe?

"External counterpulsation, per treatment session" (short descriptor "Extrnl counterpulse, per tx"), in the G section (procedures and professional services, temporary). Added 2000-01-01.

Is G0166 a CPT code?

It is not. G0166 belongs to the G section (procedures and professional services, temporary) of HCPCS Level II, the CMS code set, not to AMA CPT. "G0166 CPT code" searches refer to it.

What does Medicare pay for G0166?

National PFS payment for G0166 is $102.87 in an office and no facility amount in a facility (October 2026), built from 0.00 work, 3.04 practice-expense and 0.04 malpractice RVUs at $33.4009 per RVU. Qualifying APM participants get $103.39 at $33.5675.

How many units of G0166 can be billed per day?

CMS caps G0166 at practitioner 2 (MAI 3, Nature of Service/Procedure); hospital outpatient 2 (MAI 3, Nature of Service/Procedure) units per day in the 2026 Q4 MUE tables. For the practitioner MUE (MAI 3), units above 2 deny for the day but can be paid on appeal with documentation; denials arrive as CARC 151.

Does Medicare cover G0166?

No current LCD or billing article lists G0166; its HCPCS coverage code is D (special coverage instructions apply).

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.

Disclaimer

This page is an operational reference compiled from CMS publications: the HCPCS Level II file, the physician, DMEPOS and clinical laboratory fee schedules, OPPS and ASC addenda, NCCI MUE, PTP and add-on edit tables and the Medicare Coverage Database. Amounts are Medicare national figures before locality and state adjustment; Medicaid and commercial payers set their own. CPT codes are shown as numbers only; CPT descriptors are copyright AMA. Nothing here is legal, clinical or billing advice.

Found a figure that does not match the CMS file? Report a data correction with the CMS file and the value you expected; the request reaches the editorial team through the contact form.