Introduction: Health systems require instruments that allow for the generation of precise, clear, real, concrete, specific, and objective information that can be named, classified, shared, and compared internationally. Objetivo: Identify the scope of the ABCDEF (Trejo-Amador U, Legorreta-Rojas M, 2024) Mnemonics to transform information recording systems by applying a comprehensive tool that strengthens primary information sources and allows for the calculation of underreporting of diagnoses. Method: The ABCDEF form was applied to a sample of 825 clinical records from 8 high-productivity hospitals located in central Mexico. The primary sources of information were the medical admission notes, progress notes, discharge notes, and the hospital discharge report (HDR). Results: The areas of opportunity identified in the Mnemonics, primarily in the HDR, are the use of abbreviations and diagnostic specificity. A subreporting of diagnoses is documented between the discharge medical note and the HDR of 40%, with a range of 21 to 61%. Conclusions: Strengthening the primary sources of information outlined in the mnemonic ABCDEF in the records, mainly in the HDR, allows for a clearer epidemiological profile, improves decision-making, and transforms the health conditions of workers, their families, students, and each of the beneficiaries.