ObjectiveTo find the relative security range of blood biochemical indexes of children with cleft lip and palate to tolerant the operations in order that more timely treatments would be taken and the sequential therapies would get their best results.MethodsThe preoperative blood biochemical indexes of 985 completed cases of children with cleft lip and palate were analyzed retrospectively in this study, cross correlation using a variety of statistical analysis methods.ResultsThe inner 95% of the reference values of total bilirubin, direct bilirubin, indirect bilirubin, albumin, creatinine, lymphocytes and red blood cells were all contained in their standard reference value ranges. However, the inner 95% of the reference values of white blood cells, platelets, plasma-albumin/globulin(A/G), alanine aminotransferase(ALT), and aspartate transaminase(AST) were higher than their standard reference value ranges, and the inner 95% of the reference values of hemoglobin, total protein, globulin and serum urea were lower than their standard reference value ranges. The values of hemoglobin, total protein, albumin, globulin and serum urea significantly differed between different sex-groups, and these values in female group were significantly higher than those in male group. The values of red blood cell, hemoglobin, total protein, globulin, serum urea and creatinine of children with simple cleft lip were all higher than those of children with simple cleft palate or cleft lip and palate, while the values of lymphocyte, total bilirubin, direct bilirubin, indirect bilirubin, ALT and AST of children with cleft lip and palate were higher than those of children with simple cleft lip or simple cleft palate.ConclusionThe values of white blood cells, platelets, lymphocytes, A/G, ALT, and AST of children with cleft lip and palate may be higher than those of adults. During the preoperative assessment, this study can provide references of the relatively safe biochemical indicators for c operations to catch the best time for operation. In the meantime, the risks in the operations should be noticed as well.