Nephrology CPT Codes: Complete 2026 Coding and Billing Guide

Three codes that have not been billable since January 1, 2017 still appear in nephrology code lists published this year: 36147, 36148 and 36870. CPT replaced them with the bundled 36901 to 36909 family nine years ago.

That is the pattern in nephrology. The codes change less often than the rules around them, and the rules are where claims fail. One monthly payment covers each dialysis patient. A modifier facilities appended for years stopped counting in July 2026. Imaging guidance has been bundled into renal biopsy since 2016. This guide covers nephrology billing and coding across every code family a practice reports, sourced throughout to CMS, the AMA and the FY 2027 ICD-10-CM release. If you would rather hand the work to a team that does this daily, our nephrology billing services cover the full cycle. 

What Are Nephrology CPT Codes?

Nephrology CPT codes report dialysis and its oversight, the access that makes dialysis possible, the interventions that keep it working, kidney biopsy and transplant, and the visit and care management services around them. Unlike most specialties, nephrology does not bill primarily per encounter. Its largest recurring line is a monthly payment, and several families are bundled hierarchies where the more extensive code absorbs the lesser one.

Family	Range	Billing unit	Claim
Dialysis procedures	90935–90999	Per session or day	Professional
ESRD monthly capitation	90951–90970	Per calendar month	Professional
Vascular access	36800–36870	Per procedure	Professional
Circuit interventions	36901–36909	Per session, bundled	Professional
Peritoneal access	49418–49422	Per procedure	Professional
Kidney procedures	50200–50547	Per procedure	Professional
E/M and care management	99202–99498	Per encounter or month	Professional
ESRD facility services	90999, G0491	Per treatment or line	Facility

The last row is the one most code lists omit. The ESRD CPT codes span both claim types: capitation on the professional side, 90999 and G0491 on the facility side. The difference between professional and institutional claims decides which form, which codes and which modifiers apply. 

Dialysis Procedure Codes (90935 to 90999)

The dialysis CPT codes in the 90935 to 90999 range report the session itself. They are not how you bill routine outpatient maintenance dialysis for an ESRD patient, which is paid through capitation. CMS places 90935 and 90937 with inpatient ESRD hemodialysis and with outpatient dialysis for patients not on the ESRD benefit, such as acute kidney injury.

Code	What it reports
90935	Hemodialysis, single physician or QHP evaluation
90937	Hemodialysis, repeated evaluations, with or without substantial revision of the prescription
90940	Hemodialysis access flow study, indicator dilution method
90945	Dialysis other than hemodialysis, single evaluation. Peritoneal, hemofiltration, CRRT
90947	Dialysis other than hemodialysis, repeated evaluations
90989 / 90993	Dialysis training, complete course / per session when incomplete
90999	Unlisted dialysis procedure. Carries the G1 to G6 adequacy modifier on the facility claim

Source: CMS Medicare Claims Processing Manual, Chapter 8, sections 50.8, 50.9 and 170.

Choosing the right hemodialysis CPT code comes down to the number of evaluations inside the session, not the complexity of the patient. 90937 pays more and is a known audit target, so each evaluation needs its own documented assessment with its own timing and trigger.

For CRRT in the ICU, 90945 and 90947 are reported per day because the therapy is continuous. CAPD and APD delivered at home to an ESRD patient belong in the monthly home capitation codes instead. On training, a facility may bill 25 sessions per patient for hemodialysis and 15 each for CAPD and CCPD, with the MAC deciding on anything beyond 15.

ESRD Monthly Capitation (90951 to 90970)

The ESRD CPT codes in the 90951 to 90970 range are the recurring revenue line in a nephrology practice. Medicare pays the managing physician one monthly amount. Three facts select the code: age, setting, and face-to-face visits in the calendar month.

Patient age	4+ visits	2 to 3 visits	1 visit	Home, full month	Per day
Under 2 years	90951	90952	90953	90963	90967
2 to 11 years	90954	90955	90956	90964	90968
12 to 19 years	90957	90958	90959	90965	90969
20 years and older	90960	90961	90962	90966	90970

Age is taken at the end of the month billed. Source: CMS Claims Processing Manual, Chapter 8, section 140.

Five rules decide whether these claims pay.

• One capitation claim per patient per calendar month, however many physicians were involved.
• At least one face-to-face visit is required, including for the home codes where no visit tier appears.
• Visits by partners and NPPs in the group count toward the tier, subject to your MAC’s rules.
• Each counted visit needs its own dated, signed note. Four claimed and three documented is a downcode.
• Routine dialysis-related E/M is already inside the monthly payment.

When a hospitalization, transfer, transplant or new start splits the month, the per-day codes replace the full-month code entirely. A patient hospitalized seven days and managed as an outpatient for the other twenty-three is billed twenty-three units.

Vascular Access Codes

Three facts in the operative note decide the code: creation or revision, autogenous or graft material, and whether a thrombectomy was performed.

Code	What it reports
36800	Cannula insertion for hemodialysis, vein to vein
36810	External arteriovenous cannula, Scribner type
36815	Arteriovenous cannula revision or closure
36818 / 36819 / 36820	Open AV anastomosis: upper arm cephalic, upper arm basilic, forearm vein transposition
36821	Direct open AV anastomosis, any site, Cimino type
36825 / 36830	Fistula creation other than direct anastomosis: autogenous / non-autogenous graft
36831 / 36832 / 36833	Open thrombectomy / revision / revision with thrombectomy
36834	Plastic repair of arteriovenous aneurysm
36835	Insertion of Thomas shunt
36836 / 36837	Percutaneous AV fistula creation, upper extremity. Single / separate access sites
36838	Distal revascularization and interval ligation, the DRIL procedure
36860 / 36861	External cannula declotting, without / with balloon catheter
36558 / 36589	Tunneled central venous catheter insertion (age 5+) / removal

36870 sat in this family until it was deleted on January 1, 2017. Source: AMA CPT code set; CPT Assistant, October 2022, for 36836 and 36837.

Clot removed with nothing revised is 36831. Revised with no clot is 36832. Both in one session is 36833, a single code. Codes 36836 and 36837 include all access, angiography, imaging guidance and same-session maturation work, so none of that is separately reportable on the day of creation. Both carry a 0-day global, so maturation on a later date is.

Dialysis Circuit Interventions (36901 to 36909)

This is the most misreported family in nephrology. Before 2017 the work was built from component codes. CPT deleted those and replaced them with nine bundled codes that include the radiological supervision and interpretation, so there is no separate imaging code.

Deleted in 2017 and still quoted: 36147, 36148 and 36870, along with the supervision codes reported with them, among them 35475, 35476, 75791 and 75962. If a code list still carries them, it predates 2017.

Patent circuit	Thrombosed circuit	Service
36901	36904	Diagnostic angiography / thrombectomy or thrombolysis
36902	36905	Plus angioplasty, peripheral segment
36903	36906	Plus stent, peripheral segment
+36907 / +36908		Central segment angioplasty / stent. Add-ons only
+36909		Embolization, once per encounter per day

Only one base code per session, and only the most intensive service. Segment definitions follow the AMA CPT code set; the detailed wording comes from CMS LCD L34062, which binds one jurisdiction.

The peripheral segment runs from the arterial anastomosis through the axillary vein, not the subclavian. All angioplasty inside it is reported once, however many lesions. A separate central stenosis can be reported again with the add-ons. If the circuit was reached from a femoral or other separate access, the base code carries modifier 52.

Peritoneal Dialysis Access

Code	What it reports
49418	Tunneled intraperitoneal catheter, percutaneous. Includes imaging guidance, placement, contrast and supervision
49421	Tunneled intraperitoneal catheter for dialysis, open
49422	Removal of a tunneled intraperitoneal catheter

Laparoscopic placement is 49324. The subcutaneous extension with a remote chest exit site, 49435, is an add-on to 49324 or 49421 and is routinely missed.

The question between 49418 and 49421 is approach, not catheter type. Because 49418 includes its guidance, no separate guidance code is reported with it.

Kidney Biopsy

Code	What it reports
50200 / 50205	Renal biopsy, percutaneous by trocar or needle / by surgical exposure
76942 / 77012	Ultrasound / CT guidance for needle placement

Guidance is bundled into 50200. Effective January 1, 2016, CMS added 76942, 77001, 77012 and 77021 as NCCI Column Two codes paired with 50200. Reporting the biopsy and the guidance together is an unbundling edit. Guidance published before 2016, and some since, still instructs readers to bill 50200 and 76942 together. Check the modifier indicator on the current quarterly file before assuming an override exists, and document the guidance either way.

Kidney Transplant Codes

Group	Codes
Recipient	50360 without recipient nephrectomy; 50365 with
Donor	50300 cadaver; 50320 open living donor; 50547 laparoscopic living donor
Backbench	50323 cadaver prep; 50325 living donor prep; 50327 / 50328 / 50329 venous, arterial, ureteral reconstruction, each
Modifiers	62 co-surgeons in different specialties, 62.5% each; 66 team, by report; 80 / 82 assistant, 16%

Donor nephrectomy codes include cold preservation, so it is not separately reportable. Source: CMS Global Surgery, MLN907166.

E/M Codes in Nephrology

Range	Category
99202–99215	Office or outpatient, new and established
99221–99223 / 99231–99233	Initial / subsequent hospital inpatient or observation
99238–99239	Hospital discharge day management, splitting at 30 minutes
99291–99292	Critical care, first 30 to 74 minutes and each additional 30

Can you bill an office visit on a dialysis day? Only when the service is significant, separately identifiable, and not part of the management the monthly payment covers. Routine assessment of access, adequacy, anemia and phosphorus sits inside capitation, and modifier 25 does not make it payable. A problem outside the ESRD management does, documented as a self-contained service with its own diagnosis.

CCM, TCM and Advance Care Planning

Code	Service and threshold
99490 / +99439	CCM, clinical staff. First 20 minutes, then each additional 20
99487 / +99489	Complex CCM. First 60 minutes, then each additional 30
99495 / 99496	TCM, moderate / high complexity. Face-to-face within 14 or 7 days, contact within 2 business days
99497 / +99498	Advance care planning. First 30 minutes, then each additional 30

Source: CMS Chronic Care Management, MLN909188.

CMS states you cannot bill CCM during the same service period as 90951 through 90970, because the monthly payment already includes the care coordination. CCM is therefore for the CKD population before dialysis and for post-transplant patients, not the dialysis panel. CCM and TCM are not mutually exclusive, and practices routinely leave one unbilled. Our chronic care management billing services handle the monthly time validation these codes require. 

Nephrology ICD-10 Codes

FY 2027 ICD-10-CM took effect October 1, 2026. The N18 family carried no additions or deletions.

Code	Description
N18.1 / N18.2	CKD stage 1 / stage 2, mild
N18.30 / N18.31 / N18.32	CKD stage 3 unspecified / 3a / 3b
N18.4 / N18.5 / N18.6	CKD stage 4 / stage 5 / end stage renal disease
N18.9	CKD unspecified
N17.0–N17.9	Acute kidney failure, by type
Z99.2	Dependence on renal dialysis
I12.0 / I12.9	Hypertensive CKD with stage 5 or ESRD / with stage 1 to 4
I13.0 / I13.10 / I13.11 / I13.2	Hypertensive heart and CKD, by heart failure status and stage
E11.22	Type 2 diabetes with diabetic chronic kidney disease
N25.81	Secondary hyperparathyroidism of renal origin
E87.0–E87.6	Hypernatremia, hyponatremia, acidosis, hyperkalemia, hypokalemia

Source: CDC/NCHS ICD-10-CM Official Guidelines, FY 2027.

N18.3 is not billable alone. Stage 5 CKD and ESRD are not the same thing, and a stage 5 patient not yet on renal replacement therapy is N18.5. Where hypertension accompanies CKD, the I12 or I13 code is sequenced first and the N18 code follows to identify the stage.

Modifiers for Nephrology

Nephrology uses two separate modifier sets. Conflating them is the most common structural error in published nephrology coding guidance.

Professional claim	Facility claim, ESRD facility only
25 separately identifiable E/M	G1 to G5 urea reduction ratio bands
59, XE, XS, XP, XU distinct service	G6 fewer than seven sessions in the month
26 / TC professional and technical	V5 / V6 / V7 access type
50 bilateral. For Medicare, one line item	V8 / V9 terminated April 1, 2012
LT / RT laterality	AY service not for ESRD treatment
76 / 77 repeat, same or different physician	AX retired July 1, 2026
90 / 91 reference lab; repeat lab test
93 audio-only telemedicine
GV / GW hospice indicators

Source: CMS Claims Processing Manual, Chapter 8, section 50.9.

One of G1 through G6 must appear with HCPCS 90999 on at least one hemodialysis revenue code line, or the claim is returned. V5 is required whenever a catheter is present even when it is not the access in use, which means two modifiers on that line. Under Medicare, claims for ESRD patients in hospice lacking GV or GW will deny; commercial payers handle hospice indicators differently.

RVUs and Reimbursement

Conversion factor	Applies to	2026	Change
Qualifying APM	Clinicians qualifying in an advanced APM	$33.5675	+3.77%
Non-qualifying APM	Everyone else, including traditional MIPS	$33.4009	+3.26%

Both rose from $32.3465 in 2025. Source: CMS CY 2026 PFS Final Rule, CMS-1832-F.

The efficiency adjustment reduces work RVUs for procedural and diagnostic services but not time-based ones. Dialysis procedures, access work and circuit interventions take the reduction; capitation, E/M and care management do not. A conversion factor increase above three percent therefore does not mean a raise for a procedure-heavy practice.

Per-code RVUs are not published here. Published tables are inconsistent, some inverting 90935 and 90937, and RVUs change every January. Pull yours from the CMS Physician Fee Schedule Look-Up Tool, filtered to your MAC locality and setting. How RVUs convert into payment is covered in our guide to profee coding. 

Global Periods

Indicator	Meaning	Total length
000	Endoscopy or minor procedure	Procedure day only
010	Minor procedure	11 days, no pre-operative day
090	Major surgery	92 days: 1 before, the day of, 90 after
XXX	Global concept does not apply	E/M and capitation codes
ZZZ	Add-on code	Takes the primary code’s period
YYY	Contractor-priced	MAC sets 0, 10 or 90 days

Indicators are assigned per code and revised. Source: CMS Global Surgery, MLN907166.

For a return inside a 90-day window, modifier 58 covers a planned or more extensive staged procedure and starts a new period. Modifier 78 covers an unplanned return and does not. Modifier 79 covers an unrelated procedure and starts a new period. Modifier 78 carries a condition the others do not: the return must be to a room equipped and staffed solely for procedures. An access intervention in a procedure suite qualifies; the same work at the bedside does not.

NCCI Edits and MUE Limits

Where nephrology hits edits	The pairing
Inside the circuit family	36901 with 36902 or any higher code, same session
Renal biopsy guidance	50200 with 76942, 77001, 77012 or 77021
Peritoneal access guidance	49418 with a separate guidance code
Open access work	36831 and 36832 instead of 36833
Session codes against capitation	90935 or 90937 inside a billed capitation month

Confirm pairs against the quarterly file current on the date of service. Source: CMS NCCI Policy Manual.

Each edit carries a modifier indicator: 0 means no modifier will bypass it, 1 means a modifier may be used where the circumstances justify it, 9 means the edit has been deleted. MUEs carry an adjudication indicator: 1 is a claim line edit, 2 is absolute with no override, 3 may be paid on appeal. CMS treats an MUE denial as a coding denial, not a medical necessity denial.

Place of Service

POS	Setting	Medicare rate
65	End-Stage Renal Disease Treatment Facility	Non-facility
11	Office	Non-facility
10 / 02	Telehealth in the patient’s home / other than home	Non-facility / Facility
22 / 23	On-campus outpatient hospital / emergency room	Facility

Source: CMS Place of Service Code Set and Transmittal 12823.

POS 65 is paid at the non-facility rate despite its name. CMS lists the ESRD Treatment Facility among non-facility settings alongside the office and the patient’s home. Confusing 65 and 11 therefore does not change the Medicare rate, but it misreports where the service happened. Telehealth is where the rate genuinely moves: POS 10 pays the higher non-facility rate and POS 02 the facility rate, and the delivery modifier does not affect it.

Common Denials and Fixes

CARC	Usual nephrology cause	Fix
18	Second capitation claim for a month already billed, often by a partner	Confirm who holds it. If the month split, rebill per-day codes for your days
97	Session code or E/M inside the capitation month, or an unbundled circuit code	Withdraw the line, or resubmit with the X modifier that states the reason
16	Missing GV or GW, missing modifier or units	Read the RARC, which names the missing element
50	Diagnosis does not support the service, commonly N18.6 without Z99.2	Correct the coding and sequencing
151	Units exceed the MUE, or the tier exceeds what is documented	Verify against the current file; bill the tier the record supports
4	Modifier 26 or TC mismatch, missing laterality	Match the component to the setting
B15	Add-on code without its base code	Submit the base code or confirm it was on the prior claim

Reason codes are maintained by X12; both lists update quarterly. Duplicates normally carry group code OA.

Three habits prevent most of these. Record who holds the capitation claim for each patient. Build a hospice enrollment check into eligibility, because nothing in the workflow announces it. And audit thirty capitation claims against the visit documentation, the highest-yield audit in nephrology billing. For claims already past that point, our denial management and AR recovery teams work the backlog.