The goal of this review was to investigate the usefulness of a wound swab (using the Levine or Z technique) in comparison with a biopsy as a reliable method for the diagnosis of a chronic wound infection.
A literature review using the electronic databases PubMed, CINAHL, and MEDLINE were searched by strategy. A total of 6 articles fulfilled the inclusion criteria.
The Levine technique detects more organisms in acute wounds, as well as in chronic wounds, than the Z technique. Comparing both with the biopsy as criterion standard, the diagnostic accuracy to diagnose a chronic wound infection by the Levine technique was higher in comparison to the Z technique. At a threshold of 3.7 × 104 microorganisms per swab, the Levine technique had a sensitivity of 0.90, a specificity of 57%, and a positive predictive value and negative predictive value of 0.77 and 0.91, respectively. Description of the method of swab taking was diverse and not uniform.
Only a few studies in the literature compare wound swabs with biopsies for the diagnosis of chronic infected wounds. Until now, the Levine technique has been considered as the most reliable and valid method, but there is an urgent need for a well-designed study with a sufficient number of patients to optimize the diagnostic accuracy of chronic infected wounds.
The best sampling technique for taking a swab has not yet been identified and validated. Until then, the authors recommend the Levine technique.