The story of the Dermatophyte Test Strip - Ivan Bristow PhD & Michelle Score BSc (Hons)
February 1, 2019
It’s always good to have new innovations in podiatry and when something does come along that can revolutionise practice its always exciting. Back in 2014, we were reading an article which was published in the British Journal of Dermatology (1). The article caught our attention because it discussed a development in the diagnosis of dermatophyte nail disease. Having been frustrated by the difficulties of ascertaining an accurate diagnosis with current methods an alternative was certainly welcome. The current clinical podiatry standard of diagnosing fungal nail infection just by clinical appearance was at best was insufficient and at worst, unethical.
The 2014 published study from a Japanese research group compared the test strip with conventional microscopy and culture from 165 nail samples. The results were impressive showing a very high sensitivity rate of 98%. Moreover, the advantages of the test were appealing to us as clinicians. Taking just five minutes to reach an accurate diagnosis with no need for high levels of technical skill? This would be great for a podiatrist, we thought. A second paper was then published which really confirmed its use. In a study of 222 nail samples, the dermatophyte test strip outperformed traditional microscopy showing high levels of accuracy (2).
Having read these articles, we were keen to obtain some samples to try out this test to see if it had a place in the podiatry clinic. Obtaining these was not straightforward but eventually, through a colleague overseas, we were able to obtain some. Needless to say, the product transformed our practice. When patients came in with a dystrophic nail, for the first time ever we were able to test the nail to check for dermatophytes instead of guessing. Having this new tool was also a learning experience. It was surprising that when we tested our ourselves using visual inspection versus the test strip, we were getting the diagnosis wrong around 25% of the time. Now patients could receive a diagnosis and begin treatment at the same appointment with no three-week wait as the samples did not have to go to the lab and of course, no disappointment when they came back a month later saying the lab specimen was negative.
At this point, we realised that the test kit was something special which should be in any clinic diagnosing and treating nail problems. So we brought the test into the UK and Ireland for clinical use. Since that time, it has been introduced throughout hundreds of podiatry clinics throughout the UK and continues to grow. For the first time, podiatrists can now reliably and quickly test for dermatophyte nail infection and increase their business. No more guessing and no more costly laboratory samples. In addition, this is a unique product which means a podiatry clinic can establish itself offering something which is not currently elsewhere. Most importantly, it also meets the guideline set by NIHCE (3) and the British Association of Dermatologists (4), namely that fungal nails should be properly diagnosed before any treatment is commenced – maintaining high clinical and ethical standards.
1. Tsunemi Y, Takehara K, Miura Y, Nakagami G, Sanada H, Kawashima M. Screening for tinea unguium by Dermatophyte Test Strip. Br J Dermatol. 2014;170(2):328-31.
2. Tsunemi Y, Hiruma M. Clinical study of Dermatophyte Test Strip, an immunochromatographic method, to detect tinea unguium dermatophytes. The Journal of Dermatology. 2016;43(12):1417-23.
3. National Institute for Health and Care Excellence. Clinical Knowledge Summaries: Fungal Nail Infection: National Institute for Health and Care Excellence; 2013 [cited 2014 April 2014]. Available from: http://cks.nice.org.uk/fungal-nail-infection#!scenariorecommendation.
4. Ameen M, Lear JT, Madan V, Mohd Mustapa MF, Richardson M. British Association of Dermatologists’ guidelines for the management of onychomycosis 2014. Br J Dermatol. 2014;171(5):937-58.