A Multi-centre, Controlled, Prospective Cohort Study Investigating the Accuracy of the Glycologic Limited Test Kit to Detect Bacterial Infection in Chronic and Delayed-healing Wounds.

The occurrence of diabetic foot ulcer (DFU) is a common complication of diabetes with enormous cost implications, totalling £650 million per year once associated morbidity is taken into account (NHS Diabetes report). Bacterial infection of wounds carries the risk of further degenerative complications including cellulitis, necrotising fasciitis, and sepsis (Grothier, 2015). Specific wounds, such as diabetic foot ulcers may lead to amputation if osteomyelitis develops. An additional undesirable effect of infection of wounds is that it delays - or stops altogether - the wound healing process (Halbert et al, 1992).

Detection of DFU infection remains reliant on clinical judgement. For example, imaging modalities such as MRI do not perform better than clinical appraisal in terms of sensitivity and specificity when it comes to detecting osteomyelitis (Dinh et al, 2008). O'meara and colleagues (2006) concluded from a systematic review on clinical examination, sample acquisition and sample analysis in DFUs that there is a lack of evidence regarding what samples should be taken and how they should be analysed. They did suggest that semi-quantitative sample analysis - a category that the Glycologic detection kit (called GLYWD) would fall under - may be a useful alternative to quantitative analysis. Quantitative detection of infection is still undertaken by swabbing the wound and then culturing the pathogens in a microbiology laboratory. Obtaining these results generally takes days; even molecular profiling does not give an instant result. Microbiological counts and species identification do not necessarily reflect infection as defined by other assessments, as demonstrated by Gardner et al (2014).

Clinical guidelines stipulate that the only available laboratory-based diagnostic option, microbiological testing, should only be used to identify the pathogen strain in clinically confirmed infection. Therefore, clinical opinion is the mainstay of predicting and diagnosing infection (NICE, 2008, 2015). The lack of a simple cost-effective and repeatable testing method may have three consequences: 1) lack of uniformity in diagnosis, due to differences in clinical judgement, which in turn may result in 2) over-diagnosis of infection with inappropriate prescription of antibiotics or antimicrobial dressings, or 3) late presentation of patients with systemic signs and spreading cellulitis or osteomyelitis requiring hospital admission and treatment with intravenous antibiotics or emergency surgery.

The provision of a rapid, reliable, sensitive and relatively low cost infection detection test kit for infection, which can be used at point-of-care, has the potential to provide the NHS with significant cost savings as well as improving the outcomes for patients. Therefore, in this study the Glycologic diagnostic wound infection detection test (GLYWD) is evaluated against clinical opinion and microbiological diagnostics to determine if it is an effective tool for the rapid detection of chronic wound infection.