EVs have much potential as sensitive, novel biomarkers because they represent the status of their cells of origin and can be used to detect cancer earlier than alternative biomarkers. The size of EVs can be determined by tunable resistive pulse sensing (TRPS). However, TRPS is susceptible to environmental noise, including mechanical and electrical noise that limits detection precision. To overcome these noises, an external device was designed, guided by flow simulations, to reduce noises that interfere with TRPS measurements. Both mechanical and electrical environmental noise reductions were observed after using the shield. The study also validated the noise reduction function of the shield by quantifying EVs from different cell origins. This study demonstrates innovation in designing shielding enclosures using composite material to improve the sensitivity of emerging tunable resistive pulse technology to quantify EVs below 200 nm, which is challenging using traditional quantification methods.