February 15, 2010

Acute Renal Failure Update — Responses to Common Coding Issues
For The Record
Vol. 22 No. 3 P. 29

A simple definition of acute renal failure is the sudden loss of kidney function resulting in partial or complete failure to filter waste products from the bloodstream with an accompanying accumulation of those waste products. The Acute Dialysis Quality Initiative proposed a classification scheme in 2004 called RIFLE: Risk, Injury, Failure, Loss, and End stage. Included in RIFLE was the definition of failure (any one of the following would indicate failure):

• a threefold increase in serum creatinine;

• a 75% decrease in glomerular filtration rate;

• 24-hour urine output of less than 0.3 mL/kg per hour; or

• anuria for 12 hours.

Acute renal failure is classified to ICD-9-CM category 584 with the specific code assignments as follows:

• 584.5, Acute kidney failure with lesion of tubular necrosis; Lower nephron nephrosis; Renal failure with (acute) tubular necrosis; Tubular necrosis, not otherwise specified; Acute tubular necrosis

• 584.6, Acute kidney failure with lesion of renal cortical necrosis

• 584.7, Acute kidney failure with lesion of renal medullary (papillary) necrosis; Necrotizing renal papillitis

• 584.8, Acute kidney failure with other specified pathological lesion in kidney

• 584.9, Acute kidney failure, unspecified; Acute kidney injury (nontraumatic)

Acute Kidney Injury
Physicians are now documenting the term acute kidney injury (AKI) to indicate damage to the kidney due to a rapid loss of renal function. Using the RIFLE criteria, AKI is defined as creatinine two times baseline or urine output of less than 0.5 mL/kg per hour for 12 hours. As of October 1, 2008, AKI (nontraumatic) is included in code 584.9.

Acute Renal Failure Secondary to Dye
Acute renal failure secondary to intravenous pyelogram dye is assigned to code 584.9 and code E947.8, Drugs/medicinal substances causing adverse effects in therapeutic use, as long as the test and dye were administered correctly. This is considered an adverse effect since the drug was given properly and the patient had a reaction to the substance that was administered correctly. For coding purposes, if the patient had an adverse reaction, the manifestation is sequenced as the principal diagnosis.

Acute Renal Failure in a Kidney Transplant Patient
If the patient is status post-kidney transplant and coming to the facility with acute renal failure, then sequence the complication of a transplanted kidney (996.81) as the principal diagnosis. “Either preexisting conditions or medical conditions that develop after the transplant are coded as complications of the transplanted organ only when they affect the function of that organ” (AHA Coding Clinic for ICD-9-CM, 1998, third quarter, pages 3-7).

Acute renal failure will affect the function of the transplanted kidney. Coding Clinic provides good examples of conditions that will affect transplanted organ function. Those conditions will affect the transplanted organ and therefore are coded as complications.

Acute Renal Insufficiency
Acute renal insufficiency (593.9), which refers to the early stages of renal impairment, is the sudden decrease of normal kidney function. Basically, it is abnormal lab results, including mildly abnormal elevated values of serum creatinine or blood urea nitrogen and diminished creatinine clearance. Treatment is directed toward treating the underlying cause without progressing to renal failure. Coders should not assign a code based on abnormal laboratory results alone; code assignment is based on physician documentation of a specific diagnosis.

Occasionally, physicians use the terms acute renal insufficiency and acute renal failure interchangeably. The physician should document the condition he or she believes is most appropriate based on the patient’s clinical picture. From a coding perspective, acute renal failure provides a more thorough description. The coder may need to ask the physician for clarification if the documentation is inconsistent or conflicting among the attending and consulting physicians.

Azotemia
If the physician documents azotemia, assign code 790.6, Abnormal blood chemistry. Prerenal azotemia is assigned to code 788.9, Other symptoms involving urinary system. However, it is appropriate to query the physician for clarification if acute renal failure is present.

Coding and sequencing for acute renal failure are dependent on the physician documentation in the medical record and application of the Official Coding Guidelines for inpatient care. Also, use specific AHA Coding Clinic for ICD-9-CM and American Medical Association CPT Assistant references to ensure complete and accurate coding.

— This information was prepared by Audrey Howard, RHIA, of 3M Consulting Services. 3M Consulting Services is a business of 3M Health Information Systems, a supplier of coding and classification systems to more than 5,000 hospitals worldwide. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payers as the result of the misuse of this coding information. More information about 3M Health Information Systems is available at www.3mhis.com or by calling 800-367-2447.