ModifiedCurativePolicy CHP-IP-2026-051

Acute Kidney Injury

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This policy governs medical necessity for acute inpatient admission, observation versus outpatient management, level-of-care assignment, continued stay, discharge readiness, and related services for members with acute kidney injury, including AKI superimposed on chronic kidney disease. It applies to Curative commercial PPO and EPO members in fully insured, level-funded, and self-funded plans.

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ModifiedCurativePolicy CHP-IP-2026-051

Acute Kidney Injury

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Sign up for curative Policy CHP-IP-2026-051 alerts

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Policy Summary

PayerCurative

PolicyAcute Kidney Injury

Policy CodePolicy CHP-IP-2026-051

Change TypeModified

Effective DateN/A

Next Review DateN/A

Key ActionDocument baseline creatinine, including source and date, current creatinine trend, and KDIGO stage.

SourceLink

POLICY UPDATE CHANGES

The applicable ICD-10-CM list adds N14.11, N14.19, and N13.6 for drug- and contrast-induced nephropathy and pyonephrosis.

The applicable ICD-10-PCS list adds 5A1D70Z, 5A1D80Z, 5A1D90Z, 0T9030Z, and 0T9130Z for renal replacement therapy and percutaneous nephrostomy.

KDIGO 1-3AKI severity framework

24-48 hoursTypical observation period for stage 1 AKI

pH <7.15Severe acidosis threshold

K+ >=6.5ICU hyperkalemia threshold

3Added ICD-10-CM codes

5Added ICD-10-PCS codes

Acute Kidney Injury Medical Necessity

Inpatient admission

Covered when ALL of the following are met.

Clinical severity finding: At least one of the following: KDIGO stage 2 or 3 AKI; stage 1 AKI that has not improved after 24 to 48 hours of observation with fluid repletion and nephrotoxin removal; oliguria with urine output below 0.5 mL/kg/h for 12 hours or anuria; potassium 6.0 mmol/L or higher, or above 5.5 mmol/L with ECG changes; metabolic acidosis with pH below 7.25 or bicarbonate below 15 mmol/L; volume overload with hypoxemia or pulmonary edema not responding to oral diuretics; uremic encephalopathy, pericarditis, or intractable nausea; obstructive AKI requiring urgent decompression; or suspected rapidly progressive glomerulonephritis or acute interstitial nephritis requiring urgent evaluation and immunosuppression.
Hospital-level service: At least one of the following: intravenous fluid therapy with strict intake-output and creatinine and potassium monitoring every 8 to 12 hours; intravenous diuretics for volume overload with monitoring; treatment of hyperkalemia or acidosis requiring cardiac monitoring or repeated intravenous therapy; intermittent or continuous renal replacement therapy; urgent urologic or interventional decompression; or urgent kidney biopsy or intravenous immunosuppression for suspected disease.

Observation or outpatient instead of inpatient

Observation is appropriate when ALL of the following apply. Outpatient management with repeat testing within 48 to 72 hours is appropriate for stage 1 AKI with an obvious reversible cause when oral intake can be maintained.

Observation criteria: KDIGO stage 1 AKI; potassium below 5.5 mmol/L, pH 7.30 or higher, and bicarbonate 18 mmol/L or higher; no volume overload, uremic symptoms, or obstruction requiring intervention; and a likely reversible cause expected to respond within 48 hours.

Outpatient management: Stage 1 AKI with an obvious reversible cause, ability to maintain oral intake, and repeat testing arranged within 48 to 72 hours.

Intensive care unit level

ICU placement is appropriate when ANY of the following is present.

Intensive care unit: Need for continuous renal replacement therapy because of hemodynamic instability; potassium 6.5 mmol/L or higher with ECG changes or arrhythmia not resolving with initial therapy; severe acidosis with pH below 7.15 and hemodynamic compromise; pulmonary edema requiring noninvasive or mechanical ventilation; or AKI with septic shock or other multi-organ failure.

Step-down or intermediate care

Step-down or intermediate care is appropriate when ANY of the following is present and ICU criteria are not met.

Step-down or intermediate care: Potassium 6.0 to 6.4 mmol/L or peaked T waves requiring continuous telemetry and repeat potassium every 2 to 4 hours; volume overload requiring high-dose or continuous intravenous diuretic with hourly urine output; or uremic encephalopathy without airway compromise.

ICU criteria must not be met.

Medical-surgical unit level

A medical-surgical bed is appropriate when ANY of the following applies and higher-level criteria are not met.

Medical-surgical unit: Stage 2 or 3 AKI with stable potassium and hemodynamics under evaluation and treatment; intermittent hemodialysis in a hemodynamically stable patient; or post-decompression monitoring after nephrostomy or stent placement.

Higher-level criteria must not be met.

Discharge readiness

Discharge is appropriate when ALL of the following are met.

Discharge readiness: Creatinine is declining or stable at a new baseline for at least 24 hours; potassium is 3.5 to 5.5 mmol/L without intravenous therapy and bicarbonate is 18 mmol/L or higher or at CKD baseline; the member is euvolemic or managed on an oral diuretic regimen with adequate urine output for baseline; no uremic symptoms, with oral intake and medications tolerated; if dialysis-dependent, an outpatient dialysis unit, schedule, and access plan are confirmed; and medication reconciliation includes nephrotoxin avoidance and renal dosing, nephrology follow-up is arranged within 1 to 2 weeks or sooner if dialysis-dependent, and repeat chemistry is planned within 48 to 72 hours.

Continued-stay criteria

Continued stay is medically necessary when ANY of the following is documented.

Continued stay: Creatinine is still rising or has not plateaued; ongoing renal replacement therapy is required with complications not manageable as an outpatient, or outpatient dialysis is not yet arranged for a dialysis-dependent member; hyperkalemia, acidosis, or volume overload requires intravenous therapy; or the underlying cause, including sepsis, obstruction, or glomerulonephritis, still requires inpatient treatment.

Review every 12 hours for stage 3 AKI or dialysis and every 24 hours otherwise.

Extended-stay review

Days beyond the planning benchmark require a documented extended-stay trigger. The benchmark is a planning tool and is not a limit on covered days.

Extended-stay trigger: New dialysis dependence awaiting stabilization of access and outpatient unit placement; continuous renal replacement therapy; glomerulonephritis requiring biopsy and immunosuppression; sepsis or obstruction with infection; or AKI on advanced CKD with complications.

Planning benchmark: Expected length-of-stay benchmarks are 4.2, 2.9, and 2.2 days for renal-failure MS-DRGs 682, 683, and 684, respectively, and 10.0, 5.3, and 2.8 days for other kidney and urinary tract procedure MS-DRGs 673, 674, and 675, respectively.

These benchmarks do not limit covered days. Review every 12 hours for stage 3 AKI or dialysis and every 24 hours otherwise.

Does not meet criteria

The following scenarios do not meet medical-necessity criteria and are referred for physician review.

Does not meet criteria: Admission for stage 1 AKI with a clear reversible cause, normal potassium and acid-base status, and the ability to take oral fluids; continued stay solely to watch creatinine decline after the cause is corrected and electrolytes are stable; pre-emptive or accelerated renal replacement therapy as the sole reason for ICU stay without conventional indications; or days awaiting an outpatient dialysis chair after the member is otherwise stable.

These scenarios are referred for physician review and are not denied by an automated system or non-physician reviewer. Days already authorized are not retroactively denied.

This policy does not address AKI caused by rhabdomyolysis, tumor lysis syndrome, or hepatorenal syndrome; those cases are reviewed under the corresponding condition-specific policies: A047, A055, and A043. Maintenance dialysis for end-stage kidney disease is outside the scope of this policy.

Inpatient admission is not medically necessary under this policy for stage 1 AKI with a clear reversible cause, normal potassium and acid-base status, and the ability to take oral fluids. Observation or outpatient management with repeat testing is appropriate; such requests are referred for physician review rather than denied by an automated system or non-physician reviewer.

A continued inpatient stay solely to observe creatinine decline after the underlying cause has been corrected and electrolytes are stable does not meet medical-necessity criteria. The member may be monitored with outpatient laboratory testing; requests in this circumstance are referred for physician review.

An ICU stay is not supported solely by pre-emptive or accelerated renal replacement therapy when the member has no conventional indication for RRT. Accelerated initiation did not improve survival and increased RRT dependence; the request is referred for physician review.

Days spent awaiting an outpatient dialysis chair do not independently support continued inpatient care after the member is otherwise stable. The case is routed to physician review and discharge planning, without retroactive denial of previously authorized days.

Diagnosis, Procedure, Revenue, and Severity Coding

ICD-10-CM: acute kidney failureICD-10

N17.0	Acute kidney failure with tubular necrosis
N17.1	Acute cortical necrosis
N17.2	Acute kidney failure with medullary necrosis
N17.8	Other acute kidney failure
N17.9	Acute kidney failure, unspecified

ICD-10-CM: drug- and contrast-induced nephropathy and pyonephrosisICD-10

N14.11	Drug- and contrast-induced nephropathy
N14.19	Other drug- and contrast-induced nephropathy
N13.6	Pyonephrosis

ICD-10-PCS: renal replacement therapy and percutaneous nephrostomyICD-10

5A1D70Z	Renal replacement therapy
5A1D80Z	Renal replacement therapy
5A1D90Z	Renal replacement therapy
0T9030Z	Percutaneous nephrostomy
0T9130Z	Percutaneous nephrostomy

MS-DRG: renal failureMS-DRG

682	Renal failure
683	Renal failure
684	Renal failure

MS-DRG: other kidney and urinary tract proceduresMS-DRG

673	Other kidney and urinary tract procedures
674	Other kidney and urinary tract procedures
675	Other kidney and urinary tract procedures

Revenue codesRevenue

0120	Revenue code
0200	Revenue code
0206	Revenue code
0250	Revenue code
0300	Revenue code
0402	Revenue code
0730	Revenue code
0762	Revenue code
0800	Revenue code
0801	Revenue code

1–10 of 14

1/2

ICD-10-CM: acute kidney failureICD-10

N17.0	Acute kidney failure with tubular necrosis
N17.1	Acute cortical necrosis
N17.2	Medullary necrosis of kidney
N17.8	Other acute kidney failure
N17.9	Acute kidney failure, unspecified

ICD-10-CM: drug- and contrast-induced nephropathy and pyonephrosis (added)ICD-10

N14.11	Nephropathy induced by antineoplastic drugs
N14.19	Nephropathy induced by other drugs, medicaments and biological substances
N13.6	Pyonephrosis

ICD-10-PCS: renal replacement therapy and percutaneous nephrostomy (added)ICD-10

5A1D70Z	Performance of urinary filtration, single
5A1D80Z	Performance of urinary filtration, multiple
5A1D90Z	Performance of urinary filtration, intermittent
0T9030Z	Drainage of right kidney pelvis with drainage device, percutaneous approach
0T9130Z	Drainage of left kidney pelvis with drainage device, percutaneous approach

MS-DRG: renal failureRevenue

682	Renal failure with major complication or comorbidity
683	Renal failure with complication or comorbidity
684	Renal failure without complication or comorbidity

MS-DRG: other kidney and urinary tract proceduresRevenue

673	Other kidney and urinary tract procedures with major complication or comorbidity
674	Other kidney and urinary tract procedures with complication or comorbidity
675	Other kidney and urinary tract procedures without complication or comorbidity

Revenue codesRevenue

0120	Revenue code
0200	Revenue code
0206	Revenue code
0250	Revenue code
0300	Revenue code
0402	Revenue code
0730	Revenue code
0762	Revenue code
0800	Revenue code
0801	Revenue code

1–10 of 14

1/2

AKI diagnostic threshold

Creatinine rise within 48 hoursSerum creatinine rise of ≥0.3 mg/dL within 48 hours

Creatinine rise within 7 daysSerum creatinine rise to ≥1.5 times baseline within 7 days

Urine outputUrine output below 0.5 mL/kg/h for 6 hours

Inpatient severity findings

Potassium

Documentation and Operational Requirements

Documentation Required

Renal Function and AKI Stage

Document the renal-function trajectory needed to establish the member’s AKI severity and current status.

Baseline creatinine, including the source and date
Current creatinine trend
KDIGO AKI stage

Documentation Required

Urine Output and Fluid Status

Record kidney output and volume status throughout the relevant admission or continued-stay period.

Urine output
Fluid balance

Documentation Required

Electrolytes and Cardiac Monitoring

Acute Kidney Injury Overview

Acute kidney injury is defined using KDIGO criteria: a serum creatinine rise of at least 0.3 mg/dL within 48 hours, a rise to at least 1.5 times baseline within 7 days, or urine output below 0.5 mL/kg/hour for 6 hours. AKI is staged from 1 through 3 according to the degree and duration of creatinine elevation or reduced urine output. Stage 1 includes creatinine 1.5 to 1.9 times baseline, or a rise of at least 0.3 mg/dL within 48 hours, or urine output below 0.5 mL/kg/hour for 6 to 12 hours. Stage 2 includes creatinine 2.0 to 2.9 times baseline or urine output below 0.5 mL/kg/hour for at least 12 hours. Stage 3 includes creatinine at least 3.0 times baseline, creatinine at least 4.0 mg/dL, initiation of renal replacement therapy, urine output below 0.3 mL/kg/hour for at least 24 hours, or anuria for at least 12 hours.

AKI Staging and Urgent RRT Indications

KDIGO stage 1 AKI

Creatinine ratioSerum creatinine 1.5 to 1.9 times baseline

Acute creatinine riseRise of 0.3 mg/dL or more within 48 hours

Urine outputBelow 0.5 mL/kg/h for 6 to 12 hours

KDIGO stage 2 AKI

Creatinine lower boundSerum creatinine 2.0 times baseline

Creatinine rangeSerum creatinine 2.0 to 2.9 times baseline

Urine outputBelow 0.5 mL/kg/h for 12 hours or more

Policy Summary

PayerCurative

PolicyAcute Kidney Injury

Policy CodePolicy CHP-IP-2026-051

Change TypeModified

Effective DateN/A

Next Review DateN/A

Key ActionDocument baseline creatinine, including source and date, current creatinine trend, and KDIGO stage.

SourceLink

On This Page

Potassium ≥6.0 mmol/L, or above 5.5 mmol/L with ECG changes

Metabolic acidosis: pHpH below 7.25

Metabolic acidosis: bicarbonateBicarbonate below 15 mmol/L

HypoxemiaSpO2 below 92% on room air with volume overload or pulmonary edema

Observation or outpatient laboratory thresholds

PotassiumBelow 5.5 mmol/L

pH7.30 or higher

Bicarbonate18 mmol/L or higher

Repeat testingRepeat testing within 48 to 72 hours when managed as an outpatient

ICU hyperkalemia threshold

Potassium thresholdPotassium ≥6.5 mmol/L

Cardiac findingsECG changes or arrhythmia

Response to therapyCardiac findings not resolving with initial therapy

Urgent RRT severe acidosis threshold

pH thresholdSevere metabolic acidosis with pH below 7.15

Urgent RRT indicationSevere metabolic acidosis with pH below 7.15 is a conventional urgent RRT indication

ICU-level concernICU placement is appropriate when pH is below 7.15 with hemodynamic compromise

Discharge electrolyte thresholds

Potassium range3.5 to 5.5 mmol/L

Intravenous therapyPotassium must be within range without intravenous therapy

Bicarbonate18 mmol/L or higher, or at CKD baseline

Include the key electrolyte and cardiac-monitoring findings that support the level of care requested.

Potassium
Bicarbonate
BUN
ECG when potassium is elevated

Documentation Required

Diagnostic Evaluation

Document the diagnostic workup performed to evaluate the cause and severity of AKI, including results when available.

Urinalysis with microscopy
Urine sodium or fractional-excretion values when obtained
Renal ultrasound

Documentation Required

Medication and Nephrotoxin Review

Show that medications were assessed for renal risk and that applicable nephrotoxins were stopped.

Medication review
Documentation that nephrotoxins were discontinued

Documentation Required

RRT and Transition Planning

When renal replacement therapy is initiated, document the clinical indication and modality, along with the transition plan for ongoing dialysis and follow-up.

RRT indication and modality when started
Outpatient dialysis arrangements
Follow-up plan

Billing Rule

Support Requested Quantity, Units, and Duration

Request only the quantity, units, and duration supported by the clinical documentation. When a service meets criteria but the request exceeds support, approve the supported portion and refer only the unsupported increment for physician review; do not treat the entire request as unsupported.

Specify the requested quantity, units, and duration.
The supported portion may be approved in full or in part; only the excess is subject to review.
An adverse determination may be issued only by a licensed physician after offering the requesting provider a peer-to-peer discussion.

Denial Risk

Low-Severity Reversible AKI

Admission for stage 1 AKI with a clear reversible cause, normal potassium and acid-base status, and the ability to take oral fluids may not meet medical-necessity criteria when observation or outpatient management with repeat testing is appropriate. Such requests are referred for physician review and are not denied by an automated system or non-physician reviewer.

Document the AKI stage, cause, potassium and acid-base status, oral-fluid tolerance, and why a higher level of care remains necessary.
Consider observation or outpatient management with repeat testing when clinically appropriate.

Denial Risk

Observation-Only Continued Stay

A continued stay solely to observe creatinine decline after the cause has been corrected and electrolytes are stable may not meet medical-necessity criteria when outpatient laboratory monitoring is appropriate.

Document ongoing inpatient needs beyond monitoring creatinine.
Explain why outpatient laboratory testing cannot safely monitor the member.

Denial Risk

Accelerated RRT Without Indication

An ICU stay based solely on pre-emptive or accelerated RRT initiation, without conventional indications, may not meet medical-necessity criteria. Accelerated initiation did not improve survival and increased RRT dependence.

Document the conventional indication for RRT and the clinical need for ICU-level care.
Do not use pre-emptive RRT alone as the basis for accelerated ICU placement.

Denial Risk

Stable Member Awaiting Dialysis Placement

Days awaiting an outpatient dialysis chair after the member is otherwise stable should be routed to physician review and discharge planning. Days already authorized are not retroactively denied.

Document the member’s current stability and remaining inpatient needs.
Record dialysis-placement efforts, discharge barriers, and the outpatient dialysis plan.
Continue concurrent review for each continued-stay period.

KDIGO stage 3 AKI

Creatinine ratioSerum creatinine 3.0 times baseline or more

Absolute creatinineSerum creatinine 4.0 mg/dL or more

Renal replacement therapyInitiation of renal replacement therapy

Urine outputBelow 0.3 mL/kg/h for 24 hours or more

AnuriaAnuria for 12 hours or more

Conventional urgent RRT indications

HyperkalemiaRefractory hyperkalemia

Severe metabolic acidosisSevere metabolic acidosis with pH below 7.15

Volume overloadRefractory volume overload with pulmonary edema

Uremic complicationsUremic pericarditis or encephalopathy

Dialyzable intoxicationDialyzable intoxication