OBJECTIVES: To assess the economic impact of introducing LacTest®, a new drug test which determines the level of hypolactasia in adults and elderly with clinical symptoms of lactose intolerance on the Spanish market. METHODS: A budget impact model was developed using the perspective of the Spanish National Health System (NHS) with a 4-year time horizon. The model was populated with data on diagnostic tests for hypolactasia, healthcare resource utilization, unit costs and market shares. The potential number of diagnostic tests annually performed in Spanish hospitals was based on a study estimating the number of patients with clinical symptoms eligible for a diagnostic test among 45 Spanish hospitals in Spain. Diagnostic tests included in this study were the hydrogen breath test plus measurements of capillary blood glucose after an overload of lactose, intestinal biopsy, fecal pH test, genetic testing and LacTest®. Costs considered were diagnostic tests, laboratory tests, physician visits and time of healthcare personnel. All costs referred to EUR 2012, using a 3% annual discount rate. Direct medical annual costs per patient with each diagnostic test were estimated before and after the introduction of LacTest®in order to estimate the total annual healthcare costs. RESULTS: The Spanish population with clinical symptoms of hypolactasia eligible for a diagnostic test was estimated to be constant at 126,420 during the next four years. Total healthcare costs were estimated at €81.7 million without the introduction of LacTest® and at €89.7 million after its introduction. CONCLUSIONS: The introduction of LacTest® only shows a moderate increase in the total costs for the Spanish NHS. LacTest® though is a test with a high reliability which decreases the need for repeating the test and the cause for additional costs as is the case with some of the other diagnostic tests compared in this study.