Background Immune thrombotic thrombocytopenic purpura (iTTP) is a rare and life-threatening thrombotic disorder. Therapeutic plasma exchange (TPE) remains the mainstay treatment, with thawed plasma (TP) being the primary product used. Liquid plasma (LP), derived from whole blood donations and stored at 4°C, shares the same expiration as the corresponding unit of whole blood and primarily serves as a bridge to TP for emergency transfusions. While the efficacy of coagulation profiles in TP and LP is well-documented, there is limited information on the stability of ADAMTS13 activity during the shelf life of these products and the experience of LP utilization in iTTP management. Methods Ten units of LP from distinct whole blood donations were collected on day 27. Ten units of TP from products frozen within 24 hours (PF24) were collected on day 6. Two units of LP within 5 days of collection underwent longitudinal sampling until day 30, with the initial collection designated as day 0. ADAMTS13 activity was assessed using fluorescence resonance energy transfer (FRETS) and ELISA-based assays. A retrospective study was performed to identify the use of LP in TPE for iTTP patients in our institute from June 15, 2019, to January 1, 2023. Results The average level of ADAMTS13 activity in 10 LP units was 0.97±0.14 IU/mL by FRETS assay, with a median of 0.967 IU/mL (range: 0.79-1.22 IU/mL). For 10 TP units, the average level of ADAMTS13 activity was 0.89±0.13 IU/mL with a median of 0.91 IU/mL (range: 0.63-1.05 IU/mL). No statistically significant difference was observed between the two products regarding ADAMTS13 activity on day 1 post-expiration (P=0.1717). ADAMTS13 activity in LP consistently remained stable over the 30-day observation period. ELISA results were consistent with FRETS assay findings. The retrospective analysis showed that seven iTTP patients with nine acute episodes received a total of 93 TPE sessions, of which, 25 (26.9%) included LP. The amount of LP was 23.7±19.7% of total plasma units. The median number of TPE sessions per episode was 10, which was comparable to that in the literature. All patients achieved complete remission, and no adverse events associated with the use of LP were observed. Conclusion Both liquid plasma and thawed plasma exhibit comparable and sustained ADAMTS13 activity throughout their shelf-life. A successful utilization of LP during TPE in a small cohort of iTTP patients suggests that LP may be a potential alternative to TP in the management of iTTP.