Current Practice for Imparting Carrier Status Detected by Newborn Screening for Sickle Cell Disorders and Cystic Fibrosis in England

Background Tandem mass spectrometry (MS/MS) has recently become an alternative method for the newborn screening of sickle cell disorders (SCD), as it is able to detect haemoglobin (Hb) peptides following digestion of bloodspots with trypsin. Using the SpOtOn Diagnostics Reagent Kit, we previously developed a screening protocol to detect only the disease states of SCD, using action values based on the ratio between the variant Hb peptide to wild-type peptide abundances for the HbS, C, DPunjab, OArab, E and Lepore peptides. Methods Action values using the ratios between the wild type HbA (ßT1-3) peptides and the foetal Hb (γT2) peptide were developed to identify bloodspot samples from premature and transfused infants. An evaluation was undertaken to assess the transferability of the action values onto an additional MS/MS instrument. We report here our experience using this MS/MS protocol. Results During a three-year period, we screened 100,456 babies and identified 10 SCD cases (1 HbS/HPFH, 5 HbS/S and 4 HbS/C) and a case of HbE/ß-thalassaemia that was identified as a by-product. The Hb variant to wild-type peptide ratio action values were transferable to a second MS/MS instrument. Our protocol prevented the identification of an estimated 810 carrier infants. Gestational age-related action values for HbA to HbF peptide ratios were required to minimize the number of samples referred for second-line testing to exclude ß-thalassaemia. Conclusion MS/MS is a robust alternative screening technology for SCD; in addition, it also optimizes the use of equipment and expertise that currently exist in newborn screening laboratories.

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Newborn screening for haemoglobinopathies by high performance liquid chromatography (HPLC): diagnostic utility of different approaches in resource-poor settings

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2014-0452 ◽

2014 ◽

Vol 52 (12) ◽

Cited By ~ 3

Author(s):

Dipti S. Upadhye ◽

Dipty L. Jain ◽

Yogesh L. Trivedi ◽

Anita H. Nadkarni ◽

Kanjaksha Ghosh ◽

...

Keyword(s):

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

Newborn Screening ◽

Sickle Cell ◽

High Performance ◽

Diagnostic Utility ◽

Gene Deletions ◽

Major Health ◽

Sickle Cell Disorders ◽

Normal Baby

AbstractSickle cell disease is a major health burden in India. The aim of the study was to compare the diagnostic utility of two different approaches on automated high performance liquid chromatography (HPLC) for newborn screening for sickle cell disorders and other haemoglobinopathies in India.Newborn babies of sickle heterozygous mothers were tested by HPLC using two different kits, the β-thal short kit, which is routinely used for screening for haemoglobinopathies in most laboratories, and the sickle cell short kit which is specific only for neonatal samples. Confirmation of the sickle and α genotypes was done by molecular analysis.Of the 601 babies tested, 276 were normal, 284 were sickle heterozygous and 41 were sickle homozygous using the β-thal short kit. Using the sickle cell short kit, a discrepancy was seen in one newborn sample where a normal baby was identified as a sickle heterozygous baby. α-Genotyping was done in 42 babies and 16 of them had α gene deletions. The presence of α thalassaemia could be suspected in 15 of these 16 babies based on a spike at the start of the chromatogram using the β-thal short kit. In comparison, using the sickle cell short kit the diagnosis of α thalassaemia was difficult based on the percentage of the FAST peak. Further, other rare α chain Hb variants were also missed.The β-thal short kit was more versatile than the sickle cell short kit for screening for haemoglobinopathies in newborns in our population.

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