Respiratory illness and chronic lung disease affect millions of people worldwide, causing close to 14 million Emergency department visits in the US in 2020. To diagnose and monitor some of these diseases like asthma and COPD, pulmonary function tests, or PFTs, are given. One example is a peak flow test, in which a small plastic device is blown into by a patient to record the maximum output. When a patient blows into this device, the small aerosol particles in their breath are spread into the surroundings, putting staff at risk of contamination with any possible diseases like COVID and flu. With the recent pandemic, it has become even more important to protect other patients and healthcare workers from possible spread when these tests are given. Our solution is specifically designed to reduce aerosol spread and the risk of cross-infection, using a two-piece reusable filter that can be attached to the start of the peak flow device. Silicone material allows it to attach to any PFT while providing an airtight seal. The shell of the device will be reusable with HEPA grade filter paper on the inside. This filter will have O rings on either side, to create a proper seal when the shell is screwed together. HEPA filters can be changed as frequently as preferred by the staff, but at a minimum of every 6 months. The device was tested to ensure it did not impede on the current results of the PFT and validated so that there was a greater than 90% reduction in aerosol particles. With the filtering technology and compatibility capability, Go with the Flow is the perfect solution for a clinic or hospital administering peak flow tests.