Does this patient have a chronic wound infection?

Another article from JAMA series of articles on the rational clinical examination:

JAMA, February 8, 2012 - vol. 307, No. 6

The only proven indicator on history was INCREASING PAIN, however lack of it did not rule out infection.

Other symptoms and signs, which are commonly used, were not helpful in making the diagnosis, i.e.
- Erythema
- Edema
- Heat
- Foul odor
- Discolored granulation tissue
- Serous exudate
- Purulent exudate
- Sanguinous exudate
- Delayed healing
- Wound breakdown
- Pocketing

Classic signs of wound infection, evaluated in isolation from the clinical context and other findings, are not particularly helpful in diagnosing infection in a chronic wound (LR 0.8-2.3). Available studies suggest that the character of wound fluid exudates is most likely not useful as predictor of infection when the reference standard is a deep tissue biopsy culture.

What is interesting, when IDSA criteria for diagnosing infected diabetic foot ulcers were studied, they were found to lack utility (Se and Sp 50%), which turned out to be both surprising and dissapointing, it highlights the difficulty of making the diagnosis.

Non-invasive test that appeared promising - quantitive swab culture with Levine technique - swab is rotated an area of 1x1 cm for 5 seconds with sufficient pressure to extract fluid from within the wound tissue. Positive test made infection more likely, negative test made it less likely.