2027 ICD-10-CM Diagnosis Code Z49.31Encounter for adequacy testing for hemodialysis

ICD-10-CM Codes›Z00–Z99›Z40-Z53›Z49

ICD-10-CM Z49.31
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z49.31 is a billable ICD-10-CM diagnosis code for encounter for adequacy testing for hemodialysis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 698 through 700. The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. Coders also document this condition as adequacy of dialysis - finding. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Chronic kidney disease and Other aftercare encounter.

Z49.31 no longer risk-adjusts for Medicare Advantage: it mapped to HCC 134 under the retired CMS-HCC V24 model through payment year 2025 but maps to no category in the live V28 model. It still risk-adjusts in the PACE (CMS-HCC V22) category 134, ESRD (V21) category 134, ESRD (V24) category 134, and RxHCC Part D (V08) category 261 for payment year 2027.

Code Identity

ICD-10-CM Code
Z49.31
Billable Status
Yes — Valid for Submission
Code Describes
Encounter for adequacy testing for hemodialysis
Short Description
Encounter for adequacy testing for hemodialysis
Same as the full description in the CMS dataset.
Parent Code
Z49.3
Encounter for adequacy testing for dialysis

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ40-Z53Encounters for other specific health care
CategoryZ49Encounter for care involving renal dialysis
This CodeZ49.31Encounter for adequacy testing for hemodialysis

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z49.31.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Present on Admission (POA)Billing

Z49.31 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Encounters for other specific health care (Z40-Z53).

Medicare Risk Adjustment (HCC)Billing

Z49.31 no longer risk-adjusts for Medicare Advantage: it maps to no payment category in the live CMS-HCC V28 model, although it still risk-adjusts in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
Dropped in V28 see all codes that no longer risk-adjust
Prior Model (CMS-HCC V24)
HCC 134
V24 retired last contributed to a Medicare Advantage risk score in payment year 2025
Other CMS Models
PACE (CMS-HCC V22): HCC 134 · ESRD (V21): HCC 134 · ESRD (V24): HCC 134
ESRD V21 weights: 0.000 dialysis, 0.000 functioning graft · ESRD V24 weights: 0.000 dialysis, 0.000 functioning graft
Part D (RxHCC)
RxHCC 261 — Dialysis Status, Including End Stage Renal Disease
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adequacy of dialysis - finding
  • Adequacy of hemodialysis
  • Finding of measures of dialysis
  • Hemodialysis access site patent
  • Hemodialysis finding
  • Increase in hemodialysis blood flow
  • Increase in hemodialysis dialyzer size
  • Increase in hemodialysis session time

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Z49.31: its own notes plus those printed at Z49, block Z40-Z53, and Chapter 21. A note printed at a category, block or chapter applies to every code under it.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block Z40-Z53 Encounters for other specific health care applies to 164 codes
  • follow-up examination for medical surveillance after treatment (Z08-Z09)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From Z49 Encounter for care involving renal dialysis applies to 4 codes
  • associated end stage renal disease (N18.6)

Notes

General instructions on how these codes are used.

From Chapter 21 (Z00-Z99) Factors influencing health status and contact with health services applies to 1,425 codes
  • Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways:
  • (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury.
  • (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR GEN003
Chronic kidney disease
Default principal diagnosis: inpatient No · outpatient Yes
CCSR FAC010
Other aftercare encounter
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Dialysis

When your kidneys are healthy, they clean your blood. They also make hormones that keep your bones strong and your blood healthy. When your kidneys fail, you need treatment to replace the work your kidneys used to do. Unless you have a kidney transplant, you will need a treatment called dialysis.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Z49.31 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
V56.31 Hemodialysis testing
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Z49.31Overview

What is the ICD-10 code for encounter for adequacy testing for hemodialysis?

The ICD-10-CM code for encounter for adequacy testing for hemodialysis is Z49.31 (sometimes written as Z4931). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Z49.31 (Encounter for adequacy testing for dialysis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report encounter for adequacy testing for hemodialysis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Z49.31 group to?

On inpatient claims, encounter for adequacy testing for hemodialysis maps to MS-DRG 699, 698, 700, with relative weights from 0.6740 to 1.6400 depending on complications. Higher weights mean higher Medicare reimbursement.

Can Z49.31 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because encounter for adequacy testing for hemodialysis describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z49.31 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for encounter for adequacy testing for hemodialysis on inpatient claims. The code appears in the Encounters for other specific health care (Z40-Z53) range of the CMS exempt list.

Does Z49.31 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage. Z49.31 mapped to HCC 134 in the retired CMS-HCC V24 model, which last determined payment in 2025, but it maps to no category in the live V28 model; see all codes that no longer risk-adjust. It still risk-adjusts in the PACE (CMS-HCC V22) category 134 (Dialysis Status), ESRD (V21) category 134 (Dialysis Status), ESRD (V24) category 134 (Dialysis Status), and RxHCC Part D (V08) category 261 (Dialysis Status, Including End Stage Renal Disease).