Analisis Quality Control Internal Pemeriksaan Sgot dan Sgpt Menggunakan Grafik Levey-Jennings dan Six Sigma di RS X Yogyakarta: Internal Quality Control Analysis of Sgot and Sgpt Examination Using Levey-Jennings Graphics and Six Sigma at X Hospital Yogyakarta. JoH. 2025;12(1):060-068. doi:10.30590/joh.v12n1.1002