Anemia detection utilizing diffuse reflectance spectra from the palpebral conjunctiva and tunable liquid crystal filter technology

Anemia is a serious worldwide disorder affecting 2 billion people globally. While the only clinically accepted method of diagnosis remains an invasive blood draw and laboratory analysis, numerous attempts have been made to measure total blood hemoglobin noninvasively. Although the palpebral conjunctiva can be used as a poor qualitative indicator of anemia, a quantitative analysis of the conjunctiva using visible diffuse reflectance spectroscopy can provide an accurate and easy method of noninvasive measurement. Preliminary studies using a traditional grating based spectrometer have shown this method of analysis to be effective and accurate at diagnosing anemia and are presented here. An alternative device to collect diffuse reflectance spectroscopy based on tunable liquid crystal technology that is comparatively inexpensive and compact is also presented. Deformed helix ferroelectric liquid crystals (DHFLC) can be tuned fully across the visible spectrum and have a narrow bandwidth of reflection. A handheld microspectrometer facilitates this technique becoming a clinically viable method of analysis and enables total hemoglobin to be measured quickly, and without the need of a blood draw. The rapidity of this test can make total hemoglobin measurement a new vital sign, increasingly important because of the concurrent appearance of anemia with numerous other disorders.