Noninvasive Optical, Electrical, and Acoustic Methods of Total Hemoglobin Determination

Abstract

Background: Anemia is an underdiagnosed, significant public health concern afflicting >2 billion people worldwide. The detrimental effects of tissue oxygen deficiency on the cardiovascular system and concurrent appearance of anemia with numerous high-risk disorders highlight the importance of clinical screening. Currently there is no universally accepted, clinically applicable, noninvasive hemoglobin/hematocrit screening tool. The need for such a device has prompted an investigation into a breadth of techniques. Methods: A synopsis of the literature and current directions of research in noninvasive total hemoglobin measurement was collected. Contributions highlighted in this review are limited to those studies conducted with a clinical aspect, and most include in vivo patient studies. Results: The review of potential techniques presented here includes optoacoustic spectroscopy, spectrophotometric imaging, diffuse reflectance spectroscopy, transcutaneous illumination, electrical admittance plethysmography, and photoplethysmography. The technological performance, relative benefits of each approach, potential instrumentation design considerations, and future directions are discussed in each subcategory. Conclusions: Many techniques reviewed here have shown excellent accuracy, sensitivity, and specificity in measuring hemoglobin/hematocrit, thus in the near future a new clinically viable tool for noninvasive hemoglobin/hematocrit monitoring will likely be widely used for patient care. Limiting factors in clinical adoption will likely involve technology integration into the current standard of care in each field routinely dealing with anemia.

Disposable platform provides visual and color-based point-of-care anemia self-testing

“…18). This reaction has been well characterized (18)(19)(20)(21) and has been used commercially for spectrophotometric detection of Hgb in plasma, qualitative detection of blood in stool samples, and crime scene investigation and in portable single-wavelength photometers for POC anemia testing (22,23). Our group has repurposed and modified this reaction to (a) yield differential product ratios that exhibit different colorimetric properties spanning the visual spectrum, correlating with clinically relevant Hgb levels in whole blood, and (b) improve reagent stability and shelf-life.…”

“…The majority of these analyzers cost between US $1,000 and $2,000, with each test itself costing US $1-2 thereafter. More recently, noninvasive co-oximeters offering continuous Hgb level measurements have been developed, but they cost between US $1,000 and $3,000 and also require electrical power and technical training (17,22). In an attempt to introduce a simple, low-cost alternative for low-resource settings, the World Health Organization developed the Haemoglobin Colour Scale to test for anemia using the color of one's blood to differentiate between Hgb levels, such that anemic samples reflected a paler red color as compared with that of normal samples (12-16).…”

Experimental unit for in vivo measurement of hemoglobin content in blood

“…The advantages of non-invasive analysis of protein components of the blood are elimination of the risk of infection, the possibility of continuous monitoring, the lack of biological pollution, reduced requirements for staff. The estimation of the concentration of blood proteins containing chromospheres centers (like hemoglobin) in vivo may be performed by various methods (McMurdy et al 2008;Kumar 2013;Doshi and Panditrao 2013;Bender, J.E., Shang, A.B., Moretti, E.W., Yu, B., Richards, L.M., Ramanujam, N.: Noninvasive monitoring of tissue hemoglobinusing UV-VIS diffuse reflectance spectroscopy: a pilot study. Opt.…”

Choosing the probe radiation wavelengths for noninvasive monitoring of haemoglobin in blood

“…Various methods [1][2][3][4][5][6][7][8][9] can be used to assess the blood haemoglobin concentration in vivo.…”