In a retrospective review of 1177 children presenting for plastic surgical procedures, investigations were performed in 487 and abnormal results were found in 138 as defined by variation from the local laboratory reference range. Most of the abnormalities were of no clinical significance. Twenty one children had abnormal haemoglobin results (the lowest was 9 g/dl) and 101 children had clinically insignificant platelet or white cell abnormalities. One child, with a family history of sickle cell trait, was confirmed as sickle-cell trait. No case was postponed as a result of these investigations. The non-selective ordering of pre-operative blood tests leads to unnecessary patient discomfort, the potential for additional superfluous investigations and higher costs.