title: Superficial wound swabbing: a novel method of sampling and processing wound fluid for subsequent immunoassay analysis in diabetic foot ulcerations.
abstract: OBJECTIVE
  In diabetic foot ulcers, wound fluid inflammatory mediators have previously been proposed as surrogate markers for nonhealing. However, currently available wound fluid sampling techniques are not suitable for clinical practice due to low levels of exudate and a high logistical effort. The aim of this investigation was to assess 1) the technique of superficial wound swabbing for harvesting wound fluid; and 2) the quality of the collected fluid for immunoassay analysis of inflammatory mediators.
  
  
  METHODS
  Both nylon-flocked swabs and film dressings were used to collect wound fluid from foot ulcers of diabetic patients. In randomly selected patients, levels of wound fluid inflammatory mediators and matrix metalloproteases were determined using multiplexed bead-based sandwich immunoassays with respect to both sampling methods. Wound fluid spike-in experiments were performed to evaluate the impact of different sample processing protocols on subsequent immunoassay analysis.
  
  
  RESULTS
  Using the swabbing technique, a median amount of 40 µL (2-120 µL) wound exudate was collected, which allowed the measurement of several multiplex panels. Comparing both sampling methods, a similar qualitative protein recovery was observed with a trend to analyte enrichment by swabbing. Sample processing using swabs did not affect analyte recovery, with the exception of interleukin (IL)-8, thymus and activation-regulated chemokine, IL-17A, interferon-γ-induced protein 10, and IL-4.
  
  
  CONCLUSIONS
  The quality of wound fluid collected by superficial swabbing is not inferior to the current standard technique. Combined with subsequent bead-based sandwich immunoassay analysis, this new method offers a noninvasive technique, suitable for daily clinical routines, for assessment of inflammatory activity in diabetic foot ulcers.
authors: Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen, Germany.
authors: Michael
authors: M
authors: Schmohl
authors: Stefan
authors: S
authors: Beckert
authors: Thomas O
authors: TO
authors: Joos
authors: Alfred
authors: A
authors: Königsrainer
authors: Nicole
authors: N
authors: Schneiderhan-Marra
authors: Markus W
authors: MW
authors: Löffler
mesh_terms: D017719:Diabetic Foot / Q000175:diagnosis*; D005260:Female; D016523:Foot Ulcer / Q000175:diagnosis*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D020381:Interleukin-17 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D008297:Male; D013048:Specimen Handling / Q000379:methods*; D013950:Thymus Gland / Q000378:metabolism
chemical_list: D020381:Interleukin-17; D016209:Interleukin-8; D015847:Interleukin-4