Toward an Anemia Early Detection Device Based on 50-μL Whole Blood Sample

Abstract

A first approach to a portable and compact device for point-of-care (PoC) early instantaneous detection of anemia is described. This device works directly with whole blood samples relying on hematocrit analysis by means of impedance analysis. This device consists of a custom electronic instrumentation, postprocessing software and plug-and-play disposable sensor. The designed electronics are connected to a remote computer, which allows control of the instrumentation and results displaying with a user friendly software panel. The disposable sensor is based on a low-cost label-free three gold electrode commercial sensor for 50-μL volume samples. Forty-eight whole blood samples, randomly collected from hospitalized patients in Hospital Clínic, were used to validate the device capability for anemia detection. Whole blood samples were distributed in two groups: 10 samples for system calibration, and 38 samples for system validation. To calibrate the device, a complete EIS experiment has been performed to get a full impedance spectrum analysis, defining an accurate frequency working range for hematocrit detection. Afterward, we developed a protocol for instant impedance detection to determine the system detection accuracy, sensitivity, and coefficient of variation. As a result, impedance variations between different samples have been detected with less than 2% accuracy error for both impedance magnitude and phase. A hematocrit detection algorithm, relying on impedance analysis, has been developed based on the previous studies. The response, effectiveness, and robustness of the portable PoC device to detect anemia have been proved with an accuracy error of 1.75% and a coefficient of variation of less than 5%.

An Instantaneous Low-Cost Point-of-Care Anemia Detection Device

“…In this work we have adopted a configuration of three electrodes, which are defined as follows: the working electrode (WE), where electrical response of the object under investigation is measured; the reference electrode (RE), which tracks the electric signal and the counter or auxiliary electrode (CE), which supplies the current required. With this electrode configuration, the problematic behavior of the simpler two electrodes topology is avoided [ 27 ]. This configuration is defined by the WE, where the sample is placed and the electrical signal is applied, and the CE, which tracks the solution potential and supplies the current required for experience, creating a polarization effect causing a distortion of the applied electrical signal.…”

“…This phenomenon has been studied previously [ 27 ], demonstrating the feasibility of the impedance measurement technique to perform an easy, fast and sensitive hematocrit detection, evaluated through comparison with complete blood count (CBC) by using a clinical hematology analyzer, the Advia 2120 from Siemens AG (Munich, Germany). This sensing system is a low-cost disposable three-electrode sensor that works with 50 μL blood samples.…”

“…A full custom electronic circuit was specifically designed to carry out impedance measurements using a disposable three-electrode C223AT sensor. The electronic system was designed based on the specifications found in the study previously reported [ 27 ]. The architecture of the device is divided in three parts: an oscillator that provides the ac voltage signal (V CELL ), a sensor driving instrumentation and a rms-to-dc converter ( Figure 2a ).…”

“…Ramaswamy et al , [ 26 ] performed a blood coagulation test based on a custom microfluidic device and the electrical impedance detection of whole blood samples. Our group has previously studied this technique and has used it in the design of a novel anemia detection device [ 27 ]. The device presented reliable, sensitive and robust hematocrit detection, relying on low-cost straightforward electronic equipment and sensing systems.…”

“…This work presents an improvement on the previously reported device [ 27 ], as a compact, economic and portable PoC solution, for instantaneous detection of hematocrit through whole blood samples. The previously developed device relied on full spectrum analysis of blood samples by means of a Digital Lock-In Amplifier (DLIA) based on a Frequency Response Analyzer (FRA) approach.…”