Screening for haemoglobinopathies on cord blood: laboratory and clinical experience

Abstract

Objectives Blood from the umbilical cord (cord blood) is screened for haemoglobinopathies in several neonatal screening programmes, as well as before banking as a source of stem cells. We investigated the pre-analytical and analytical aspects of neonatal screening for haemoglobinopathies on liquid cord blood using the Sebia Haemoglobin kit. We give an interpretation of the results as well as a proposed scheme for reporting of the results. Methods A neonatal screening programme on liquid cord blood has been performed in all labour wards in Brussels since 1994. Using that material, the screening methods of isoelectric focusing and capillary zone electrophoresis were compared using 962 cord blood samples. From December 2008 to December 2010, 47,388 neonatal samples were analysed by capillary electrophoresis as the firstline method for neonatal screening. High-performance liquid chromatography was used as the second-line method. Results Capillary zone electrophoresis on liquid cord blood enabled the detection of all clinically significant haemoglobin variants, significant levels of Hb Bart's, and b-thalassaemia major. Among the 47,388 neonatal samples tested, 362 (0.7%) were suspected to be contaminated with maternal blood, but no diagnostic error was reported retrospectively for a major haemoglobinopathy. Recommendations for the interpretation and reporting of results of neonatal screening for haemoglobinopathies using the Sebia Haemoglobin kit are proposed. Conclusions A routine capillary electrophoresis kit adapted to neonatal screening and liquid cord blood is reliable for screening for haemoglobinopathies. It enables early detection and reporting of all major haemoglobinopathies and most minor ones. It also enables use of a simple scheme to report the results.

New approach to accurate interpretation of sickle cell disease newborn screening by applying multiple of median cutoffs and ratios

“…The putative identification of newborns affected with SCD is simple and very sensitive with the methods used. 16 14,15,19 In our study, all SCD-positive screening tests were confirmed, except for two patients not retrieved despite much effort. We did not observe, however, a high false-positive result even in the few cases of extremely preterm newborns, as described elsewhere.…”

“…Our chosen screening cutoff related to the low HbA value is currently under prospective validation (study in progress). With the expression of Hb percentages in MoM, a single threshold independent of term of pregnancy could potentially be used, in contrast to other studies where different thresholds have been chosen based on the distribution of HbA% in normal full‐term neonates …”

“…As already described, HbA% was significantly correlated with GA, and for a given GA there was very large variation in HbA concentration between individuals (Table 1). [13][14][15] In order to avoid GA dependence, we propose that the value of HbA be expressed in multiples of the normal gestation-specific median (MoM), rather than as a percentage. Regression analysis demonstrates an independence of HbA expressed in MoM versus GA.…”

Suitable Specimen Types for Newborn Biochemical Screening-A Summary

“…Contamination risk from maternal blood exists but is found to be at a low, acceptable rate in Belgian haemoglobinopathy studies [5] and English amino acid studies [6] Some contamination risk from faeces and substances on babies' skin or paper card.…”

“…Sickle cell disease (SCD) cannot be detected SCD and beta thalassaemia major screening successful and satisfactory in Belgian studies using capillary electrophoresis [5].…”