“…For instance, plasma cf-mtDNA levels may increase over decades with human aging (Pinti et al, 2014), blood cf-mtDNA levels changes over weeks to months during pregnancy (serum) (Cushen et al, 2020), with exercise training (serum) (Nasi et al, 2016), and following psychotropic treatment (plasma) (Lindqvist et al, 2018). Moreover, over much shorter time scales, studies in plasma (Hummel et al, 2018; Lindqvist et al, 2016; Shockett et al, 2016; Stawski et al, 2017), serum (Trumpff et al, 2019), and saliva (Trumpff et al, 2022) show that cf-mtDNA concentrations change several-fold over periods ranging from minutes to hours (reviewed in (Trumpff et al, 2021)), calling for longitudinal and prospective studies with repeated measures to accurately capture cf-mtDNA dynamics. Thus, the need to examine cf-mtDNA across varying timescales and broadly representative participant populations (Clayton and Collins, 2014) calls for studies with large sample sizes, compounding the need for high-throughput, cost-effective, scalable laboratory methods.…”