An international study has validated a less invasive way to diagnose mitochondrial disease using skin biopsies. Researchers at the University of Colorado Anschutz campus evaluated functional testing in fibroblasts, skin cells grown in the lab, in a paper published in EMBO Molecular Medicine. The tests are now available through the Mitochondrial Diagnostic Laboratory at Children's Colorado, making it one of North America's largest providers of mitochondrial functional testing, receiving samples from medical centres across the US and Canada. "Being able to obtain critical diagnostic information from a simple skin biopsy has the potential to make the diagnostic process more accessible and less burdensome," the researchers said. The publication is the first comprehensive evaluation of how often the tests contribute to a diagnosis and how accurately they identify mitochondrial disease. Mitochondrial diseases impair the cell's energy production and can affect many organs, and diagnosis has traditionally required invasive muscle biopsies. The expanded testing builds on years of clinical translation work at the university.