Abstract: Objective:To retrospectively analyze the serological test results of blood samples in children diagnosed with neonatal hemolytic disease(HDN),and explore the effect of specimens on the serum test results of HDN.Method:A total of 439 children diagnosed with HDN were enrolled in our hospital from March 2016 to March 2018.The HDN blood group serological test results were retrospectively analyzed and the age of the children at the time of specimen testing was recorded.Result:Among 439 children diagnosed with HDN,422 cases of ABO blood group system accounted for 96.13%;17 cases of RhN blood group system ,accounting for 3.87%.Among 439 children with HDN,blood group serological test results were all positive in 34 cases,accounting for 7.74%;direct anti-human globulin test(DAT)negative,free test and release test positive 262 cases,accounting for 59.68%;DAT and free test negative 143 cases of positive release test,accounting for 32.58%.The age of HDN children was mainly collected from 1 day to 6 days,but the positive rate of free test and DAT decreased gradually after the age of children was more than 3 days.Conclusion:The time of specimen delivery in HDN children was closely related to the detection rate.It is recommended that clinicians should conduct HDN blood group serological tests within 3 days after birth,which would be of great significance for the early diagnosis and treatment of HDN.