ICD-10 Code for Post-Operative Surgical Site Infection
The billable ICD-10 code for a post-operative patient presenting with redness and drainage from the surgical incision is T81.4 (Infection following a procedure). 1
Primary Coding
- T81.4 is the appropriate code when clinical signs of surgical site infection are present, including erythema and purulent or serous drainage from the wound. 1
- This code applies to superficial incisional surgical site infections that involve the subcutaneous space between the skin and underlying muscular fascia, occurring within 30 days of surgery. 2
Required Clinical Documentation
To support proper coding with T81.4, your documentation must include: 1
- Presence and extent of erythema (measure distance from wound edge)
- Character of drainage (purulent, serosanguinous, or serous)
- Associated local signs (pain, tenderness, swelling, warmth)
- Systemic signs if present (fever, tachycardia, elevated WBC)
- Gram stain and culture results when obtained
Timing Considerations for Accurate Coding
- Infections appearing within 48 hours are rare and typically indicate virulent organisms like Group A Streptococcus or Clostridium species, requiring different clinical urgency. 2, 3, 1
- Most surgical site infections appear between days 4-6 post-operatively and represent true infectious processes rather than inflammatory responses. 3, 1
- Fever and wound changes in the first 48-72 hours are typically non-infectious inflammatory responses and may not warrant the T81.4 code unless true infection is documented. 3
Additional Coding Considerations
- Code suture removal and incision/drainage procedures separately when performed for surgical site infections. 1
- Add organism-specific codes if MRSA or other specific pathogens are confirmed by culture. 1
- Consider additional codes for polymicrobial infections in wounds involving the perineum, GI tract, or female genital tract. 1
Common Pitfall to Avoid
Do not code isolated serosanguinous drainage without other signs of infection as T81.4. 4 Drainage alone has low specificity for surgical site infection—you need additional clinical signs (erythema >5 cm, fever >38.5°C, purulent drainage, or systemic signs) to justify the infection code. 2