Renal Failure

Documentation Tips

Do not use Acute Kidney Injury interchangeably with Acute Renal Insufficiency in documentation, these terms are not synonymous in coding guidelines.

  1. Specify the stages for Chronic Kidney Disease (1-5).

  2. AKI is recognized as an abbreviation for Acute Kidney Injury.

  3. Define the abbreviation before  including ARI, CRF, and CKD since they are not approved.

  4. Acute Kidney Injury  is a diagnosis stated without supporting evidence. If a provider documents Acute Kidney Injury or Chronic Kidney Disease in the absence of reasonable criteria, the hospital and the provider may be penalized for “inconsistency in charting.”

Indicators for Acute Kidney Injury / Chronic Kidney Disease

Serum Creatinine*

  • Glomerular Filtration Rate

  • Urine Output

  • Anemia

  • Accumulation of nitrogenous waste / Azotemia

  • Acidosis

  • Hyperkalemia

  • Sodium retention, sodium wasting

Elevated serum creatinine alone is insufficient to diagnosing AKI or CKD.
-Intracorporeal leak of urine outside of the urinary tract can lead to a rise in serum creatinine that is not due to AKI or CKD. If there is a concern for this, a Urology and/or Nephrology consult is warranted.
- If a patient has incidentally found, isolated elevated serum creatinine, a Nephrology consult is warranted for evaluation of chronic kidney disease.

AKI Definition

Acute Kidney Injury (AKI) is an abrupt reduction in kidney function based on elevation in serum creatinine level, reduced urine output, electrolyte derangement, need for dialysis, or a combination of these factors.

Pre-renal, intrinsic and post-renal causes are possible etiologies and should be documented when identifiable. A combination of causes is possible.

  1. Pre-renal AKI*

  2. Intrinsic Renal AKI

  3. Post-renal AKI

* Please document Pre-renal AKI rather than pre-renal azotomia

Risk Factors for AKI

Pre-renal (Dehydration, Hemorrhage, Sepsis, Hypoalbuminemia)

Intrinsic Renal (Acute Tubular Necrosis, Tumor lysis syndrome)

Post-renal (Obstructive Uropathy, Posterior Urethral valve)

Congenital abnormalities – Renal Hypoplasia, Dysplasia, etc.

Prune Belly Syndrome

Congenital Nephrotic Syndrome

Acquired Diseases - SLE

Hemolytic Uremic Syndrome

KDIGO Acute Kidney Injury Staging Guidelines

KDIGO Acute Kidney Injury Staging Guidelines
Stage Serum Creatinine Urine Output

1

1.5-1.9 times baseline sCr
OR
≥ 0.3 mg/dL increase

<0.5 ml/kg/h for 6-12 hours

2

2-2.9 times baseline sCr

<0.5 ml/kg/h for ≥ 12 hours
3

3.0 times baseline sCr
OR
Initiation of renal replacement therapy

 <0.3 ml/kg/h for ≥ 24 hours OR Anuria for ≥ 12 hours

Age Specific Normal Serum Creatinine + KDIGO Stage (use when baseline serum creatinine unknown)
Age* Normal sCr (mg/dL) Stage 1 Stage 2 Stage 3

2 mos. - 2 yrs.

0.2 - 0.4

0.6 - 0.75

 0.76 - 1.19 >= 1.2

3 - 6 yrs.

0.3 - 0.5

0.7 - 0.99

 1 - 1.49 >= 1.5
7 - 8

.04 - .06

 0.9 - 1.19 1.2 - 1.79 >= 1.8
9 - 10 yrs. 0.4 - 0.7 0.9 - 1.39 1.4 - 2.09 >= 2.1
>= 11 yrs 0.5 - 0.9 1 - 1.99 2 - 2.69 >= 2.7

*Staging not validated in premature neonates / small infants

If Urine Output criteria is met, urine output must be verified as insufficient urine production from the kidneys in contrast to insufficient urine passage from the body or from urine drainage tubes. If there is uncertainty over insufficient urine production or urine passage, a Urology and Nephrology consult is indicated prior to declaring the AKI diagnosis.

CKD (Chronic Kidney Disease) Definition & Staging
Stage Description GFR (mL/min/1.73m2)

1

Kidney damage with normal or increased GFR

>90

2

Kidney damage with mild decrease in GFR

60 - 89
3

Moderate decrease in GFR

 30 - 59
4 Sever decrease in GFR 15 - 29
5 Kidney failure < 15 or on dialysis

Chronic Kidney Disease is defined by any condition resulting in:

  • Reduced nephron mass and/or

  • renal injury (proteinuria) and/or

  • Glomerular filtration rate <90mL/min/1.73m2 for more than 3 months

Chronic Kidney Staging Guidelines (for all ages)

DCMC Nephrologists believe that Bedside IDMS-traceable Schwarz GFR Calculator for Children can be used to calculate the GFR value: