How to Code MRSA, Methicillin-Resistant Staphylococcus Aureus
MRSA is a type of staph bacteria that is resistant to several antibiotics. Although the CDC reports that the number of invasive, life-threatening MRSA infections is decreasing, it is still a major patient threat and often treatment of these infections carries over into the home health setting. This month we will look at the different codes that indicate MRSA.
We will start by looking at B95.62, MRSA as cause of diseases classified elsewhere, which is one of the most common codes for MRSA used in the home health setting. When documentation indicates a current infection (e.g., wound infection, UTI, etc.) caused by MRSA, and the infection does not have a combination code that includes the MRSA, this code is reported after the code for the infection itself to indicate the causal organism of MRSA. Let’s look at an example of this: Patient has a UTI caused by MRSA. The proper sequencing of this is N39.0, UTI, followed by B95.62, MRSA as cause of diseases classified elsewhere.
Two more things to remember about this code:
- This code will never be used as a primary diagnosis (the infection must be coded before it)
- When using this code, it is not necessary to include a code from category Z16.11 to indicate resistance because the resistance is included in the B95 code.
Another very common way MRSA is coded is in combination codes. Certain infections caused by MRSA have a combination code which indicates the type of infection the patient has and that the infection is caused by MRSA. The most common examples are:
- A41.02 – Sepsis due to MRSA
- J15.212 – PNA due to MRSA
Because these combination codes indicate that the infection is caused by MRSA it is not necessary to also include the B95.62 code. It is also not necessary to include a code from category Z16.11 to indicate resistance because the resistance is included in the combination code.
A few other codes to note:
- A49.02, MRSA infection, unspecified site – This code indicates that the site of the MRSA is unknown. This code should not be used to indicate an infection.
- Z22.322, Carrier or suspected carrier of MRSA – This code can be assigned for patients documented as having an MRSA colonization. Another way this may be documented in the medical record is “MRSA screen positive” or “MRSA nasal swab positive.” If a patient is documented as having both MRSA colonization and an active infection, both this code and a code for the active infection may be used.
- Z86.14, History of MRSA – This code can be assigned for a patient who has had an MRSA infection in the past which is now resolved.