Soliman HAG, et al. - Researchers analyzed 456 subjects of mean age 16 ± 5 years to investigate the factors correlated with the timing of lowest hemoglobin (Hb) level and also to estimate the demand for postoperative blood transfusion in posterior spinal fusion for adolescent idiopathic scoliosis. They observed the lowest Hb on a postoperative day 2 among 32.2% of cases and on day 3 among 33.3% of cases. On Day 2, 45.1% of postoperative transfusions happened. An incline in the probability of transfusion of 49.6 times with preoperative Hb < 11 g/dL when compared with preoperative Hb > 14 g/dL. When the surgery duration exceeded 5 and 6 h, they noted incline in the probability of transfusion by 4.3- and 9.8-fold, respectively. An increase in the probability of transfusion by 3.3- and 5.3-fold with Cobb angle > 70° and 80°, respectively, was also noticed.