Newborn screening for sickle cell disorders using tandem mass spectrometry: three years’ experience of using a protocol to detect only the disease states

Abstract

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, D, O, 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.

Newborn Sickle Cell Disease Screening Using Electrospray Tandem Mass Spectrometry

“…An update and three-year review of the Welsh screening programme was published in 2017 [8]. At the time of writing, 100,456 babies had been screened using the protocol.…”

Newborn screening for sickle cell disease in Europe: recommendations from a Pan‐European Consensus Conference

“…It was also acknowledged that other methods are emerging, e.g. matrix‐assisted laser desorption ionization‐time of flight mass spectrometry (MALDI‐TOF MS) and DNA‐based methods (Hachani et al , ; Moat et al , , ; Daniel & Henthorn, , ; Theberge et al , ; Detemmerman et al , ). There was consensus that new methods should be demonstrated to be at least as sensitive and as specific as HPLC and CE before they be adopted for routine screening.…”

Proteoforms and their expanding role in laboratory medicine

“…Although the selectivity of MRM—by detecting only the select variant peptides—avoids misclassification of co-migrating or co-eluting variants in other methodologies, an MRM approach requires prespecifying the mass-to-charge transitions of the target analytes, and thus, any variants not specified in the method (rare, unknown or novel variants) will go undetected. As such, some newborn screening programs have implemented MRM screening for only detection of HbS [ 72 , 74 ]. As most newborn screening programs already use tandem mass spectrometry to screen for other diseases, albeit targeting small molecules, employing the same instrument for sickle cell disease screening provides an attractive alternative to traditional IEF and high-performance liquid chromatography methods.…”