Sarcopenia and individual signatures of sarcopenia (i.e. low grip strength or low SMI) were diagnosed according to the EWGSOP2 algorithm.<h4>Results</h4>Plasma BDNF concentrations were 47.6% higher in participants with sarcopenia than controls (P = 0.005), and demonstrated acceptable diagnostic accuracy (areas under the curves = 0.702, 95%CI = 0.597-0.806, P = 0.002, optimal cut-off >1645 pg/ml). The gene discussed is BDNF; the disease is sarcopenia.