Heat inactivation does not alter host plasma cell-free DNA characteristics in infectious disease research

•Heat inactivation (HI) with freeze–thaw (FT) does not alter plasma cfDNA properties.•Plasma cfDNA concentration remained unchanged following HI and FT.•CfDNA fragmentomics unsignificantly altered in plasma samples with HI treatments.•HI did not significantly affect the abundance and length of sequenced plasma mtDNA.•Heat-inactivated cfDNA is reliable for liquid biopsy in infectious disease research.