OBJECTIVE: This study aimed to find the level of serum Kidney Injury Molecule-1 (KIM-1) and determine its potency as early kidney damage biomarker in transfusion dependent Beta Thalassemia patients in Dr Hasan Sadikin General Hospital.
METHOD: This preeliminary study is a cross-sectional descriptive-quantitative study and was held on July 2018. The study subjects are transfusion dependent Beta Thalassemia patients that come to Pediatric Hemato-Oncology Outpatient Clinic in Dr Hasan Sadikin General Hospital during the time of study, fulfilling our inclusion and exclusion criterias, which were collected using convenient sampling methods. The inclusion criterias was have recieved more than 10 transfusions. The exclusion criteria was the presence of kidney impairement’s sign or symptoms. We drew their blood and measured their ferritin and serum KIM-1 levels. The normal range for serum KIM-1 from previous study in mice is 12,9–17,1 pg/mL.
RESULT: From total 19 subjects in this study, 10 (52,63%) of them are girls and 9 (47,37%) are boys. The mean of age is 8.68 + 3.931; number of transfusion is 51.74 + 15.905; ferritin level is 2938.28 + 1888.51; and KIM-1 level is 25.93 + 7.47. All subjects had underwent transfusion for more than 10 times and elevated ferritin level. Out of 19 subjects, only 1 had normal KIM-1 level (17,0 pg/mL) at the time of study. 
CONCLUSION: Level of serum KIM-1 in our study is above normal range; shows its potency as early biomarker of kidney impairement in thalassemia patients. We still suggest further study with larger number of subjects and data of serum ureum and creatinine level for the assurance of the use of KIM-1 in daily practice.