Surgical Site Infection (SSI) : CDC Definitions Simplified

Superficial Incisional SSI

Stab wound, pin site infection or stitch abscess alone is not considered an SSI.

a. Time: Occurs within 30 days after any operative procedure (where day 1 = the procedure date)

AND

b. Site: Involves only skin and subcutaneous tissue of the incision

AND

c. Infection: At least one of the following –

1. Purulent drainage from the superficial incision.
2. Organism(s) identified from an aseptically-obtained specimen
   from the superficial incision or subcutaneous tissue
3. Superficial incision with atleast one of localized pain/tenderness, localized swelling, erythema or heat that is deliberately opened by a surgeon/physician/physician designee without culture or non-culture based testing
4. Diagnosis of a superficial incisional SSI by a physician or physician designee (nursing practitioner or physician assistant; diagnosis/treatment of cellulitis doesn’t meet this criteria)

Deep Incisional SSI

a. Time: Occurs within 30 (for most surgeries) or 90 days (for cardiovascular and orthopedic surgeries) after operative procedure (where day 1 = the procedure date)

AND

b. Site: Involves deep soft tissues of incision (fascia/muscles)

AND

c. Infection: At least one of the following –

1. Purulent drainage from deep incision
2. Deep incision that spontaneously dehisces or is deliberately opened by surgeon/physician/physician designee + Isolation of organism based on culture/non-culture testing + Atleast 1 of: fever, localized pain or tenderness
3. Abscess/Deep infection involving deep incision (gross anatomical/histological/imaging examination)

Organ/Space SSI

a. Time: Occurs within 30 (for most surgeries) or 90 days (for cardiovascular and orthopedic surgeries) after operative procedure (where day 1 = the procedure date)

AND

b. Site: Involves deeper soft tissues (than fascia/muscles) opened/manipulated

AND

c. Infection: At least one of the following –

1. Purulent drainage from a drain placed into organ/space
2. Isolation of organism based on culture/non-culture testing from fluid/tissue in organ/space
3. Abscess/Deep infection involving organ/space (gross anatomical/histological/imaging examination)

Based on CDC definitions: https://www.cdc.gov/nhsn/pdfs/pscmanual/9pscssicurrent.pdf