Pre-Exposure Prophylaxis (PrEP) is up to 99% effective at preventing HIV when taken daily. However, poor adherence has limited its effectiveness. Therapeutic drug monitoring (TDM) has shown early promise for improving PrEP adherence. A method of TDM for PrEP, which is noninvasive, affordable, and delivers rapid results, was needed. In 2013, Drs. Giffin Daughtridge and Helen Koenig a PrEP clinic in Philadelphia. To improve PrEP adherence, they developed a lab-based mass spectrometry (LC-MS) assay that would quantify concentrations Tenofovir (TFV), which is a metabolite of one of the drugs in PrEP, in the urine of patients indicating to the doctor whether the patient had been recently adherent. The LC-MS test was developed in partnership with a research lab at the Children′s Hospital of Philadelphia (CHOP). The test was validated with blood plasma testing as a gold standard across two cohorts: Patients on PrEP had their TFV levels measured. Patients not on PrEP took one dose and TFV concentrations were measured daily in urine and plasma over a 7 day period. Cutoffs were validated at log levels between 10 and 1000 ng/mL to identify different levels of recent adherence. Helen and Giffin incorporated as UrSure in 2015. They took the startup through a series of incubators including the Harvard Venture Incubation Program, the Harvard Life Lab, MassConnect in the Massachussetts Biotechnol. Council, and the MassChallenge accelerator where they received significant mentorship on business development, fundraising, research, regulation, reimbursement, and other key aspects of building a life sciences company. To date, UrSure has received $1.9M in funding from Harvard University and the NIH through a Phase I and II SBIR grant, filed two patents, and is focused on scaling up the LC-MS test nationwide while also developing a POC Lateral Flow Immunoassay (LFIA) test.