Objective: To describe the use of laboratory tests by medical staff assigned to the emergency department of a hospital in Mexico. Materials and methods: A descriptive cross-sectional study was conducted from March to July 2022 with data from 351 users of an emergency department. A non-probability convenience sampling was used. The sample included medical records of individuals over 18 years of age, of both sexes, who had a laboratory report and received medical attention in the emergency department in the past seven days. Pregnant women, postpartum women and individuals in shock were excluded. The variables collected from the records included sex, age, diagnosis, admission shift, type of emergency, requested analytes, documentation of laboratory report in clinical notes, analysis of laboratory results, and initiation or modification of medical treatment based on the findings. Descriptive...