Comparing Spectrophotometric Hemoglobin Concentrations with Conventional Laboratory Cell Analyzers in Transfusion-Dependent Beta-Thalassemia Patients

Background/Objectives: Thalassemias, a hereditary condition commonly linked to chronic anemia, require regular blood transfusions and repeated blood draws for assessments of hemoglobin (Hb) content, which can be uncomfortable. A promising substitute for laboratory hemoglobin testing is non-invasive spectrophotometric hemoglobin (SpHb) monitoring; however, its applicability particularly among blood transfusion-dependent thalassaemic patients needs to be investigated. This study’s primary goal was to investigate the relationships and agreements between SpHb, g/dL, and an automated hematology analyzer (Hb, g/dL) in this particular patient population. The secondary goal was to track how blood transfusions affect SpHb, g/dL, laboratory Hb, and pleth variability index (PVI, %). Methods: In this study, sixty patients were included. A Masimo Radical-7 pulse CO-oximeter was used to measure the SpHb, and a Sysmex XN-1000 hematological analyzer measured the laboratory Hb. Results: The results revealed a significant correlation between SpHb and laboratory Hb (n = 108, r = 0.587, p < 0.001) but also demonstrated that SpHb consistently overestimated laboratory Hb levels, with a mean bias of −1.18 g/dL (95% CI: −1.4344 to −0.9267). The Bland–Altman analysis showed a good degree of reliability between this bias (SpHb–Hb) and laboratory Hb (g/dL), with an Intra Class Correlation (ICC) of 0.613 but with a wide 95% CI ranging from 0.557 to 0.736 (t = 3.817, p < 0.001). The 95% limits of agreement ranged from −3.7893 to +1.4228 g/dL. Conclusions: This significant bias restricted the application of SpHb as a trustworthy method for assessing hemoglobin levels in patients with blood transfusion-dependent thalassemia. Nonetheless, the capability to monitor SpHb and PVI variations during blood transfusions offered a real-time assessment of the impact of transfusions on patients’ hemoglobin levels and volume status.