Q&A: Coding antibiotic resistance

Q: We recently had a patient who was on oral Bactrim after a fracture who may have been non-compliant with his therapy but who indicates that he’s fully adherent to his medications. He was admitted for IV antibiotics, was given IV vancomycin, and was closely followed by the orthopedic physician. Should we use code Z16.20, Resistance to unspecified antibiotic, in this case?

A: Let’s start by defining antibiotic resistance. It is the ability of bacteria and other microorganisms to resist the effects of an antibiotic to which they were once sensitive.

Because of the limited information provided, I am unsure if this is an example of a true resistance or unresponsiveness of the bacteria to the antibiotic. It could also related to the amount of antibiotic given.

I can tell you based on the information provided in a code book, the codes from category Z16, Resistance to antimicrobial drugs, are used as additional codes to identify the resistance and unresponsiveness of a condition to antimicrobial drugs. There is a code first note for the infection. I would also suggest reading the Official Guidelines for Coding and Reporting under Section I.C.1.c. for some added information regarding these codes and the infection codes.

Take a look specifically at the code Z16.20, Resistance to unspecified antibiotic, and also take a look at code Z16.29, Resistance to other single specified antibiotic.

The difference between “unspecified” and “other specified” is that the unspecified code is used for documentation lacking in specificity, whereas the code for “other specified” is used where the specificity is present in the documentation, but the code set doesn’t have a specific code for the condition at this time.

In this situation, I would also recommend collaborating with other departments, including the pharmacy, infection control, and coding staff. They will be extremely helpful for you.

Editor’s Note: Sharme Brodie, RN, CCDS, CDI education specialist and CDI Boot Camp instructor for HCPro in Middleton, Massachusetts, answered this question. For information, contact her at sbrodie@hcpro.com. For information regarding CDI Boot Camps, click here.