|11||Noninvasive PoC Anemia Detection Device
Anemia is a condition that affects nearly 2 billion people, according to the WHO.Anemia is an entirely preventable disease, and once detected, the patient can take corrective action to restore their iron levels to a healthy state. According to Miller et al, the probability that you are affected by anemia increases five-fold in underdeveloped geographies . Current non-invasive POC detection methods can be relatively expensive, and are difficult to move from place to place which makes them all the more inaccessible to the geographies that need it most. We propose to build a more portable and cost effective non-invasive anemia detection method by combining image and spectroscopy based detection methods in a wearable device that can be taken to regions without adequate medical facilities and used to help diagnose this preventable disease.
The device we build will be required to provide accurate binary diagnosis of anemia based on both the oxygen level from a fingertip pulse oximeter, and the hemoglobin level based on RGB heuristics given by the pallor of the conjunctiva . Data collection hardware will include a low-resolution camera for detecting conjunctiva pallor and wide-band photodiodes for pulse oximetry measurements. The two detection methods will be encapsulated in a single, wearable, fingertip device that delivers at least 9 correct diagnoses out of 10. This will be accompanied by a wristband that carries the power, processing, and diagnosis indication subsystems. The device will deliver all 10 diagnoses on a single charge, and be able to deliver diagnoses even while charging.
The minimum viable product will deliver two complete detection systems for data capture, a processing system for data analysis and detection, a power system for delivering the required capacity and charging needs, and a diagnosis indicator to relay the results to the testing administrator.
The total cost of the assembled product should be less than $50.
Detection System Design
Pulse oximetry is done to non-invasively estimate the concentration of both Hb and HbO2 by measuring the absorption coefficients at two separate wavelengths . We intend to use at least wideband photodiodes, each with a filter for either red (660nm) or near-infrared (940nm), that are activated by two distinct light sources at red and near-infrared, which illuminate the tip of the finger in a 50% duty cycle. The light that perfuses the tissue is then detected by an array of wide-band photodiodes that detect the light which is transmitted through the tissue. This waveform is then offloaded to the processing subsystem, which uses the information of which light source is currently active alongside the incoming waveform to compute the ratio of AC to DC components in the detected waveform. This ratio is taken at both wavelengths, and the ratio of these ratios is used alongside a lookup table to compute an estimate of the percent saturation of O2 in the blood.
The second method of detecting anemia is to look at conjunctival pallor. The conjunctiva is the mucous membrane that covers the front of your eye and lines the under-eyelid. For many patients with anemia, the conjunctiva is distinctly pale and lacks redness . A healthy patient has a distinctly red conjunctiva . A diagnosis for anemia can be made accurately when conjunctival pallor is examined and then combined with other methods of detecting Hb levels, such as the pulse oximetry method described above.