Q&A: Sequencing sepsis complications in ICD-10-CM

Q: A patient presents with sepsis due to acute pyelonephritis (E. coli). She had a previous kidney transplant at age 10 due to polycystic kidneys (removed), has chronic kidney disease (CKD) stage 3b, and is immunosuppressed due to drugs. How would this scenario be reported in ICD-10-CM?

A: Sequenced correctly, the scenario would be reported as follows:

Primary diagnosis:

• A41.51, sepsis due to E. coli

CC:

• T86.13, kidney transplant infection
• N10, acute pyelonephritis
• D84.821, immunodeficiency due to drugs

Non-CC:

• B96.20, unspecified E. coli as the cause of diseases classified elsewhere
• N18.32, CKD, stage 3b

A couple years ago, I would have told you sepsis would just be the secondary diagnosis because there's a complication code. However, a Coding Clinic publication was recently released, and it tells coders to report sepsis first.

In ICD-10-CM/PCS Coding Clinic, fourth quarter 2023, a coder sought advice on reporting Klebsiella sepsis without septic shock due to acute pyelonephritis of a transplanted right kidney. The AHA directed the coder to sequence A41.59 as the principal diagnosis, because “When a transplant complication leads to a systemic infection, such as sepsis, sequence the sepsis as the principal diagnosis rather than a code from category T86.” This code would be followed by codes for the transplant infection, acute pyelonephritis, and acute pyelonephritis in sepsis in the situation referenced in the Coding Clinic.

Additionally, the sequencing of reporting the sepsis code first is supported by section I.C.1.d.4 of the 2024 ICD-10-CM Official Guidelines for Coding and Reporting, which says, “If the reason for admission is sepsis and a localized infection, a code for the underlying systemic infection should be assigned first and the code for the localized infection should be assigned as a secondary diagnosis.”

Now, this sequencing is completely backward from what many coders are used to. They are used to the thought that if the infection is related to a device, such as sepsis related to a foley catheter, that complication code goes before the sepsis. If we have sepsis related to an orthopedic device, then that orthopedic device complication code would go before the sepsis. But here, Coding Clinic says that if the sepsis is in a transplanted organ, the sepsis would be reported first.

So, in the case of sepsis due to E. coli, sepsis will be reported first. We'll have our kidney transplant infection, reported with code T86.13, the acute pyelonephritis, reported with code N10, and so on and so forth. Reported this way, the DRG would be 872 (sepsis without MCC), with a relative weight of 1.0299.

For the coding scenario with sepsis, the ICD-10-CM code N18.32 is listed as one of the non-CC codes. There is a "Use additional code" instruction for this code to “identify kidney transplant status, if applicable, (Z94.0),” but one is not needed here. The reason is that T86.13 is used.

The official coding guidelines say, “A status code should not be used with a diagnosis code from one of the body system chapters, if the diagnosis code includes the information provided by the status code.”

Therefore, only T86.13 is needed. This code tells us that the patient has a kidney transplant and has an infection of the kidney transplant.

Editor’s note: Penny Cassady, RN, CCDS, a CDI auditor and educator based in Houston, Texas, answered this question during the HCPro webinar, “It's Complicated: Capturing Transplant Complication Codes.” This article originally appeared in JustCoding.