Q&A: Seeing oliguric and non-oliguric renal failure in documentation

Q: I have seen documentation of oliguric renal failure and non-oliguric renal failure. What is the difference and does it impact coding?

A: We can define acute kidney injury (AKI) in terms of serum creatinine stages but we can also define it in terms of urinary output. Now the term “oliguric renal failure” is one we use where people have AKI but their urine output is less than normal.

Normal urine flow should be greater than a liter a day. If you have 500 cubic centimeters (cc) up to a normal amount of urine output in a day, then that’s what we call non-oliguric renal failure, because the patient is putting out urine. These people tend to have less injury to the kidney and have greater survival statistics and so forth.

Now if the patient’s urine flow is below 500cc a day, and this is in the face of adequate fluid replacement, then the patient is not making urine appropriately and we call those people oliguric. That indicates that the patient probably has a more severe expression of the AKI or the acute tubular necrosis.

Now if you get below 50 cc, we call that anuric. We don’t see that very often in AKI or acute renal failure but when we do, patients typically have massive necrosis and a lot of times these people have cortical necrosis. The whole surface of the kidney is ischemic. But you also can see it in bilateral urinary obstruction from tumors in the pelvis. Again, the typical AKI doesn’t produce anuria. But oliguric renal failure is not uncommon and providers try to catch people early and convert them from oliguric to non-oliguric. However, this only relates to urine flow and it really doesn’t change how you code it at all.

Editor’s Note: This article was originally published in JustCoding. Garry L. Huff, MD, CCS, CCDS, AHIMA-approved ICD-10-CM/PCS trainer and president of Huff DRG Review in Eads, Tennessee, answered this question on the HCPro webcast “Acute Kidney Injury: Use Case Studies to Improve Renal Coding, Querying.”