['Heel lancing has hitherto been the method of choice for screening tests of inborn errors of metabolism in neonates. Eutectic mixture of local anesthetic has little, if any, analgesic effect when applied to the heel of pre- and full-term infants. Today there seems to be no practical method that effectively alleviates the pain caused by heel lancing. The aim of this study was to investigate whether other methods, such as venipuncture of the dorsal side of the hand, are less painful and more efficient than heel lancing in neonates.', 'One hundred twenty healthy, full-term infants who underwent testing for phenylketonuria (PKU) were included in the study. They were randomized into three groups: a venipuncture group (VP) (n = 50), a heel-lance group with a small lancet (SL) (n = 50), or a large lancet (LL) (n = 20). Pain reactions were assessed by the Neonatal Facial Coding System (NFCS). The latency and duration of the first cry as well as the total screaming time was analyzed. The efficacy of the method was assessed by the time taken to complete the PKU test and number of times the skin had to be punctured.', 'Nociceptive response. The NFCS scores after the first skin puncture were: VP, 247; SL, 333; and LL, 460. The NFCS scores were significantly lower in the VP than in the groups subjected to heel lancing. During the first 60 seconds after skin puncture, 44% of the infants cried in the VP group, compared with 72% and 85% in the SL and LL groups, respectively. Efficacy. A successful PKU test with only one skin puncture was performed in 86% of the VP group, but in only 19% in the SL group and 40% in the LL group. The total time needed to obtain the PKU blood sample was 191 seconds (median) in the VP group, 419 seconds in the SL group, and 279 seconds in the LL group.'] Is venipuncture more effective and less painful than heel lancing for blood tests in neonates?