["European Eating Disorders Review, EarlyView. ", "\nABSTRACT\n\nObjective\nThe albumin‐globulin ratio (AGR) is a biochemical marker reflecting nutritional and inflammatory status, with significant prognostic value in chronic conditions. This study examined its association with clinical/biochemical markers in adolescents with anorexia nervosa (AN) and atypical AN (AAN).\n\n\nMethod\nThis retrospective study analysed data from 294 adolescents (103 AN, 191 AAN) aged 12–18 years, presented at an adolescent medicine clinic between 2016 and 2023. AGR values were calculated and relationship between AGR and markers of both disease severity (rate of weight loss, vital sign instability, amenorrhoea, hospitalisation need) and prognosis (rehospitalisation, menstrual recovery, achievement of target body weight) was evaluated. An ideal AGR cut‐off of 1.84 was identified using receiver operating characteristic curve analysis.\n\n\nResults\nMean AGR was higher in AN than AAN (1.85 ± 0.28 vs. 1.73 ± 0.31, p < 0.001). AGR correlated negatively with body mass index z‐score, blood pressure, and heart rate. AGR ≥ 1.84 was associated with amenorrhoea, hospitalisation need at admission, hypotension, bradycardia, hypothermia, and leucopenia. Higher AGR predicted rehospitalisation during follow‐up and longer menstrual resumption duration.\n\n\nConclusion\nUnlike other chronic conditions, a higher AGR at presentation was associated with both greater medical disease severity and poorer prognosis in adolescents with AN and AAN, possibly due to relatively preserved albumin alongside decreased globulin.\n\n"]