ICD-10 Code A49.01 – Methicillin susceptible Staphylococcus aureus infection, unspecified site (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A49.01 – Methicillin susceptible Staphylococcus aureus infection, unspecified site
What it is
A49.01 identifies a Staphylococcus aureus infection caused by a methicillin-susceptible strain when the site is not specified. Use it when the record confirms MSSA infection but does not name a more precise location.
Clinical signs
Clinical features vary; refer to documentation. Common findings in staphylococcal infection may include localized redness, swelling, pain, drainage, or systemic signs of infection, but the coded diagnosis should match the documented organism and site status.
When to use this code
Use this code when the provider documents MSSA infection and does not identify a specific anatomic site or when the site cannot be determined from the note. It is appropriate for confirmed infection, not colonization or screening. If a site is documented, code the more specific infection instead.
Do not use for
Do not use A49.01 for MRSA infection, Staphylococcus aureus colonization, or a clearly documented site-specific infection that has a more precise code. Check documentation when the organism or site is unclear.
Coding tip
Confirm both susceptibility and site status in the provider record before assigning A49.01.