| dc.description.abstract | Anemia is a serious health concern worldwide, with sickle-cell anemia leading to more severe illness and higher mortality. Globally, sickle-cell disease has historically been associated with very high early-childhood mortality, with over 45% of affected children dying before the age of 10-12 years in the absence of early diagnosis and appropriate care. While total hemoglobin measurement is routinely performed for individuals with sickle-cell anemia, clinical prognosis primarily requires quantification of hemoglobin variants such as HbS, HbF, and HbA0, which guide treatment decisions and patient monitoring. Because the disorder is lifelong and progressively affects multiple organ systems, periodic follow-up and reliable assessment of hemoglobin status remain essential. Consequently, accessible identification of SCD/SCT together with dependable Hb estimation is central to both clinical management and nationwide screening initiatives.
Current diagnostic workflows rely on Hb-Electrophoresis or HPLC for SCD/SCT classification, but none of these methods provide quantitative hemoglobin concentration, requiring an additional test for Hb estimation. These multi-step workflows depend on venous blood collection, laboratory infrastructure and trained personnel, limiting feasibility for door-to-door outreach, remote communities, and decentralized screening programs. While portable Hb meters exist, no compact platform is capable of performing both sickle-cell screening and hemoglobin estimation within a single device, leaving a significant operational gap.
High-Performance Optical Spectroscopy (HPOS) has shown that reagent-treated blood exhibits characteristic spectral signatures near 427 nm and 560 nm. The SickleCert buffer assay promotes controlled HbS polymer formation, which provides measurable spectral differences between Normal, SCT, and SCD samples. For hemoglobin estimation, the SLS assay converts hemoglobin into a stable SLS–Hb chromophore with broad absorption in the 540–580 nm region. This enables accurate Hb quantification using a 560 nm interrogation source. These wavelength-dependent absorbance behaviors make HPOS principles suitable for optical miniaturization.
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This thesis presents MicroHeme, an ultra-compact, battery-operated, pocket-scale optical transmission system that integrates SickleCert-based SCD/SCT classification and SLS-based hemoglobin estimation within a single measurement geometry. MicroHeme employs narrowband LEDs near 427 nm and 560 nm to extract dual-wavelength absorbance information without requiring a spectrophotometer. Performance characterization demonstrates excellent linearity in both channels: the 560 nm path exhibits R² = 0.99 up to an absorbance of 1.0, while the 427 nm path shows strong linearity with R² = 0.98 up to 1.7 absorbance, spanning nearly the full SickleCert-treated range where blood can reach ~1.6 absorbance. Precision remains stable across relevant conditions, with maximum deviations of ±0.0039 absorbance for the 560 nm channel and ±0.0065 absorbance for the 427 nm channel. The 560 nm channel achieves 99.3% accuracy, while the 427 nm channel achieves 99.4% accuracy in absorption measurement, supporting robust Beer–Lambert calibration and reliable spectral discrimination.
With 170 grams weight, ~0.35 Wh energy consumption, and over 4 hours of battery-powered continuous operation, MicroHeme is substantially smaller and affordable than existing HPOS-inspired devices such as TrueHeme. Its pocket-scale form factor, lightweight construction, and cable-free operation directly address the mobility needs expressed by frontline health workers for door-to-door screening. By condensing HPOS functionality into a device that can literally be carried in a pocket, MicroHeme provides an exceptionally compact platform for decentralized Sickle-Cell Anemia Screening, Diagnosis and Prognosis, aligning with our national sickle-cell anemia elimination efforts. | en_US |
