Development of a low-cost and high-throughput LC-MS method for newborn screening of thalassemia and abnormal hemoglobin disorders.

BACKGROUND

Screening and pre-symptomatic diagnosis in newborns allows early treatment of thalassemia and abnormal hemoglobin (Hb) disorders in childhood. However, there remains a lack of efficient methods to screen for hemoglobinopathies in newborns. This study aimed to establish a bottom-up mass spectrometry (MS)-based method for efficient screening of hemoglobinopathies in newborns using dried blood spot (DBS) samples.

METHODS

We developed LC-MS methodology using high-performance liquid chromatography (HPLC) combined with high-resolution mass spectrometry (HRMS). DBS samples from patients covering the most common types of hemoglobinopathies and normal controls were collected. We extracted Hb from a 3.2 mm disc punched from the DBS sample, which was then digested with trypsin to release a series of Hb-specific peptides. Using HPLC-HRMS, we identified disease-related peptides for biomarker design. Using this methodology, we built a prediction model using binary logistic regression to facilitate efficient screening.

RESULTS

This new method costs less than $1 per test and can process at least 192 samples per batch. Our methodology is fast with a sampling and analysis time of 2.6 minutes and inter- and intra-assay coefficients of variation below 14.67%. Moreover, we report low limits of quantification for the proteo-specific peptides (0.50-60.00 μg/L). No significant matrix effects or carryover were observed. Our method could give reliable results even with DBS samples stored for one month. Prospective application of this method to 2726 newborns identified 87 patients with hemoglobinopathies and achieved high screening sensitivity and specificity for deletional α-thalassemia (--) (100.00% and 100.00%), β-thalassemia (97.50% and 89.63%) and other abnormal Hb disorders.

CONCLUSIONS

We have developed a low-cost, high-throughput method for reliable screening of thalassemia and abnormal Hb disorders in newborns. This could be deployed as a first-line screening test.