BACKGROUND AND AIMS: Lipoprotein(a) (Lp(a)) is associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Our goal was to characterize patients undergoing Lp(a) testing and to assess the impact of Lp(a) testing on treatment changes and subsequent ASCVD events. METHODS: A cross-sectional and a longitudinal claims data analysis were performed on 4 million patient records in Germany. Patients were followed up for a maximum of 4 years. RESULTS: In 2015 and 2018, 0.25% and 0.34% of patients were tested, respectively. Testing was more frequent in younger women in the overall population, and in men in the ASCVD population. Patients tested for Lp(a) had more comorbidities and higher ASCVD risk compared to matched control patients. ASCVD hospitalizations were more frequent prior to the first Lp(a) test (5.55 vs 1.42 per 100/person-years). The mortality rate of the Lp(a)-tested cohort and the control group was similar. Mortality was lower in patients with prior ASCVD and Lp(a) testing compared to matched controls with prior ASCVD and no Lp(a) test (2.30 vs 3.64 per 100/person-years, p <0.001). Patients with Lp(a) test received more laboratory examinations and cardiovascular medications and had more visits with specialized physicians. CONCLUSIONS: Lp(a) testing is rarely performed even in patients with very high cardiovascular risk. Patients tested for Lp(a) have more comorbidities and a higher ASCVD risk. Lp(a) testing is associated with more intensive preventive treatment and with positive effects on clinical outcomes and survival. The data support the value of Lp(a) measurements to characterize ASCVD risk and to improve ASCVD prevention.