biostudies-literatureUnknown76(2)Caballero AVitamins are essential micronutrients obtained from the diet, required by the body in small amounts daily for proper metabolism. Monitoring their levels is necessary for detecting deficiencies and guiding supplementation in certain clinical conditions. This study aimed to update the reference values for vitamins A, B1, B6, and E, and some related ratios, adjusted to the adult population of our health reference area using liquid chromatography in a direct approach calculation (<i>n</i> = 146, age: 21-64 years, 64% females). No significant differences in vitamin levels or ratios were observed based on age and sex. We obtained reliable and updated reference values: 1.1-2.8 ‍μmol/L and 18.9-42.2 ‍μmol/L for vitamins A and E respectively, 85.9-181.6 nmol/L and 57.0-165.7 nmol/L for vitamins B1 Journal of clinical biochemistry and nutrition148-155https://www.ebi.ac.uk/biostudies/studies/S-EPMC11936734biostudies-literatureOptimizing vitamin supplementation via reference interval update of vitamins A, E, B1, and B6 using HPLC.PMC11936734Cuadros MConesa LGarriga-Edo SCaballero AGabriel-Medina PMartin-Riera VMoreno FAyora AGonzalez-Silva GSanz-Gea CBlanco-Grau APeris-Serra LVillena YfalseOptimizing vitamin supplementation via reference interval update of vitamins A, E, B1, and B6 using HPLC.Vitamins are essential micronutrients obtained from the diet, required by the body in small amounts daily for proper metabolism. Monitoring their levels is necessary for detecting deficiencies and guiding supplementation in certain clinical conditions. This study aimed to update the reference values for vitamins A, B1, B6, and E, and some related ratios, adjusted to the adult population of our health reference area using liquid chromatography in a direct approach calculation (<i>n</i> = 146, age: 21-64 years, 64% females). No significant differences in vitamin levels or ratios were observed based on age and sex. We obtained reliable and updated reference values: 1.1-2.8 ‍μmol/L and 18.9-42.2 ‍μmol/L for vitamins A and E respectively, 85.9-181.6 nmol/L and 57.0-165.7 nmol/L for vitamins B1 2025-01-01T00:00:00Z2025 Mar2025-07-13T03:04:17.706Z2025-07-13T03:04:17.706ZS-EPMC119367344015140810.3164/jcbn.24-155