Simple Paper-Based Test for Measuring Blood Hemoglobin Concentration in Resource-Limited Settings

Abstract

Background The measurement of hemoglobin concentration ([Hb]) is performed routinely as a part of a complete blood cell count to evaluate the oxygen-carrying capacity of blood. Devices currently available to physicians and clinical laboratories for measuring [Hb] are accurate, operate on small samples and provide results rapidly, but may be prohibitively expensive for resource-limited settings. The unavailability of accurate but inexpensive diagnostic tools often precludes proper diagnosis of anemia in low-income developing countries. Therefore, we developed a simple paper-based assay for measuring [Hb]. Methods A 20-μL droplet of a mixture of blood and Drabkin’s reagent was deposited onto patterned chromatography paper. The resulting blood stain was digitized with a portable scanner and analyzed. The mean color intensity of the blood stain was used to quantify [Hb]. We compared the performance of the paper-based Hb assay with a hematology analyzer (comparison method) using blood samples from 54 subjects. Results The values of [Hb] measured using the paper-based assay and the comparison method were highly correlated (R2 = 0.9598); the standard deviation of the difference between the two measurements was 0.62 g/dL. The assay was accurate within 1 g/dL 90.7% of the time, overestimating [Hb] by ≥1 g/dL in 1.9% and underestimating [Hb] by ≥1 g/dL in 7.4% of the subjects. Conclusions This study demonstrates the feasibility of the paper-based Hb assay. This simple, low-cost test should be useful for diagnosing anemia in resource-limited settings, particularly in the context of care for malaria, HIV and sickle cell disease patients in sub-Saharan Africa.

Point-of-Care Testing for Anaemia in Children Using Portable Haematocrit Meter: A Pilot Study from Southwest Nigeria and Implications for Developing Countries

“…The landing cost of the portable device is 25,000 Nigerian Naira equivalent to US$125.00 dollars (21), and the estimated cost per test, taking into considerations the cost of the strips and other consumables needed for testing, would have stood at 200 Naira (approximately $1.00 USA dollar) per patient, were they to pay for the tests. This affirms the affordability of the device whose price is quite below the landing costs of most other point-of-care devices especially those used in more advanced settings to test haematocrit or haemoglobin which often need electricity to power (13,24). In contrast, the device evaluated in this study does not depend solely on electricity to power it.…”

A microfluidic approach for hemoglobin detection in whole blood

“…In comparison, a paper-based method could detect hemoglobin from lysed blood for all ranges with a bias of 0.62 ± 1.24 g/dL. 17 Additionally, a microcuvette method with cell phone detection had a bias of 0.036 ± 0.585 g/dL for mild anemia and normal conditions. 14 While our method increases uncertainty towards normal conditions, it is more likely to give a false positive at a higher concentration than a false negative at a lower range.…”

“…14,15 Alternatively, some methods use paper to absorb treated blood prior to performing a colorimetric analysis. 16,17 In addition, a centrifugal microfluidics platform uses rigorous mixing of whole blood and chemicals prior to optical readouts. 18 While these techniques have established a capability to measure hemoglobin, they currently rely on the hemolysis of whole blood.…”

Diagnosis of iron deficiency anemia using density-based fractionation of red blood cells

“…colorimetrically (both by eye and a smartphone app) using a redox reaction, 53 4) paper-based devices, 58 5) the hematocrit estimate method, 59 and 6) the WHO Hemoglobin Color Scale.…”