The potential performance of time-to-positivity (TTP) in predicting the prognosis of individuals experiencing Bloodstream infections (BSIs) has achieved little consensus. The retrospective cohort of 1015 treatment-naive adults with community-onset monomicrobial BSIs aimed to assess the performance of TTP and modified TTP (mTTP, TTP plus transportation time) in predicting 30-day mortality after adjusting for prognostic confounders, particularly the time-to-appropriate antibiotic (TtAa). Through Spearman's correlation, a significant linear-by-linear association (ρ = -0.943, P = 0.005) was exhibited between mTTP and 30-day mortality rates, but no significant association (ρ = -0.423, P = 0.26) was disclosed between TTP and 30-day mortality rates in the overall patient population. In the logistic regression model, each additional hour of mTTP or TTP was associated with an average decrease of 5 % (adjusted odds ratio [AOR], 0.95
P = 0.001) or 3 % (AOR, 0.97
P = 0.03) in the 30-day mortality rates, respectively, after adjusting for independent predictors of 30-day mortality. In conclusion, for adults with community-onset monomicrobial BSIs, mTTP revealed a favorable performance over TTP alone in predicting short-term mortality.