Cascade Screening of β-Thalassemia in an Indian Family Using Flow Injection Analysis–Triple Quadrupole Mass Spectrometry: Comparison of Micro Sampling Approaches with Conventional Electrophoresis

Background: β-thalassemia is a rare genetic disorder affecting 1–5% of the global population and poses a health burden due to migration of individuals from endemic regions. Identifying asymptomatic β-thalassemia carriers is essential to prevent the birth of thalassemic babies. A simple, sensitive method compatible with self-sampling could enhance the detection of β-thalassemia in the population. Methods: Capillary blood was collected via dried blood spot (DBS) and dried blood matrix (DBM) from 18 members (52.9%, 18/34) of a three-generation family. Hemoglobin was extracted, and globin chains were analyzed on a triple quadrupole mass spectrometer (TQMS). δ/β (%) was utilized as a biomarker to identify β-thalassemia. Venous blood collected from positive and negative individuals (n = 11) was further tested to confirm the findings and validated with complete blood count (CBC) and Capillary Electrophoresis (CE). Results: β-thalassemia was detected in seven individuals: three from generation I, three from generation II, and one from generation III. CBC showed thalassemia indices, while CE demonstrated elevated HbA2 consistent with β-thalassemia. Molecular sequencing of two samples confirmed the heterozygous c.92 + 5 G > C mutation in the β-globin gene. The overall prevalence of β-thalassemia in the family was 20.6% (7/34). High clinical performance was achieved across sample types, with 100% sensitivity for DBS, 100% specificity for DBM, and an overall accuracy of 91% when compared with CE. Conclusions: TQMS in combination with CBC parameters successfully identified asymptomatic heterozygous β-thalassemia carriers using self-sampling techniques. Cascade screening within affected families emerges as a possible strategy for early detection of β-thalassemia pending comprehensive validation.