The value of preoperative estimation of haemoglobin in children undergoing tonsillectomy. Preoperative estimation of haemoglobin in children undergoing tonsillectomy is routinely practised in most centres. To assess the value of this investigation the haemoglobin of 250 consecutive children undergoing tonsillectomy was estimated. Two children were clinically found anaemic preoperatively, and this was confirmed on blood testing. Since the prevalence of anaemia is low, it is proposed that the practice of routine preoperative estimation of haemoglobin is unnecessary, traumatic and expensive, and therefore requires reconsideration. 