Newborn screening for sickle cell disease was fully implemented throughout England in 2006. Data received from the 13 newborn screening laboratories in England show 666,060 babies were screened in 2007/08via the blood spot card. Of these,359 were identified with significant sickle cell conditions requiring follow up and treatment.During the same time period 9,452 babies were identified as carriers of haemoglobin variants and 3,725 babies received a blood transfusion prior to screening.1Theoutstanding area of grave concern in newborn screening for sickle cell relates to the possibility of babies being undiagnosed as having sickle cell disease,due to having a blood transfusion prior to a blood spot sample being taken. These babies do not have a valid sickle cell screen result. Currently,the Guidelines for Newborn Blood spot Testing recommend taking one blood spot prior to transfusion.2Alternatively, if this is not carried out,the recommendation is for repeat testing at 4 months post last blood transfusion using a liquid sample of blood.However this is challenging as it is a difficult, costly and very time consuming process for primary care and specialist counselling staff to administer. For babies that have multiple transfusions,the repeat testing policy could result in a considerable delay in being tested for sickle cell disease with the potential risk of missing a baby with the condition. The difficulties with the repeat testing process are well highlighted by audit data from Sheffield Children‟s Hospital which showed that only 3 babies out of 24 were retested in a timely manner following transfusion.3At King‟s College Hospital,4over an 18 month period,347 requests for follow up of transfused babies were sent out. Of these,252 samples should have been returned to the laboratory(excluding deaths; non-transfused babies; out of area babies and 12 already re-screened), but only 71repeatsamples were completed-28% of the expected number.