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Low-cost, rapid test for iron and vitamin A deficiencies

Mehta
Saurabh Mehta

Cornell University engineers and nutritionists have created a swift solution for a challenging global health problem: a low-cost, rapid test to detect iron and vitamin A deficiencies at the point of care.

"Vitamin A and iron deficiency affect more than one-third of the world's population. Problems resulting from these deficiencies – such as blindness, anaemia and death, particularly among children and women – are a major public health challenge," said Dr Saurabh Mehta, associate professor of global health, epidemiology and nutrition in the division of nutritional sciences, and a senior author on this new research.

The small, portable diagnostic system about the size of a lunchbox contains a blood sample test strip, like those used by diabetics.

The group found a way to include on the test strip three types of antibodies, which bind to specific biomarkers in the individual's serum. "The sampling process is similar to picking up iron among other metals," said first author Zhengda Lu, a doctoral candidate.

The strip measures concentrations of retinol binding protein (important for eyesight), C-reactive protein (an infection indicator) and the protein ferritin (to find anaemia). The test takes just 15 minutes to complete.

"We must address the micronutrient problem at the individual level – which is a much easier task. The key to solving these micronutrient deficiency problems is early detection and early intervention," said David Erickson, the Sibley College professor at Cornell's Sibley School of Mechanical and Aerospace Engineering, a senior author on the paper.

"Having information, we can change or supplement diets, if we know who is deficient – and we are more likely to prevent complications, and keep children and women healthy."

At any given time, about 250m preschool-age children globally are deficient in vitamin A, according to the World Health Organisation. In those regions where childhood deficiencies are prevalent, pregnant women are likely vitamin A deficient and anaemic, as well. Annually, up to 500,000 vitamin A-deficient children around the world become blind and about half of those children die within a year, as they become vulnerable to other diseases.

"Doctors and health professionals have sought to reduce the burden of micronutrient deficiencies and their consequences, but it's difficult since we must detect them early on to have the largest impact," said Mehta. "Most developing countries don't have access to the needed, sophisticated tools to enable early diagnosis. This test has the potential to solve that."

Abstract
Micronutrient deficiencies such as those of vitamin A and iron affect a third of the world’s population with consequences such as night blindness, higher child mortality, anemia, poor pregnancy outcomes, and reduced work capacity. Many efforts to prevent or treat these deficiencies are hampered by the lack of adequate, accessible, and affordable diagnostic methods that can enable better targeting of interventions. In this work, we demonstrate a rapid diagnostic test and mobile enabled platform for simultaneously quantifying iron (ferritin), vitamin A (retinol-binding protein), and inflammation (C-reactive protein) status. Our approach, enabled by combining multiple florescent markers and immunoassay approaches on a single test, allows us to provide accurate quantification in 15 min even though the physiological range of the markers of interest varies over five orders of magnitude. We report sensitivities of 88%, 100%, and 80% and specificities of 97%, 100%, and 97% for iron deficiency (ferritin <15 ng/mL or 32 pmol/L), vitamin A deficiency (retinol-binding protein <14.7 μg/mL or 0.70 μmol/L) and inflammation status (C-reactive protein >3.0 μg/mL or 120 nmol/L), respectively. This technology is suitable for point-of-care use in both resource-rich and resource-limited settings and can be read either by a standard laptop computer or through our previously developed NutriPhone technology. If implemented as either a population-level screening or clinical diagnostic tool, we believe this platform can transform nutritional status assessment and monitoring globally.

Authors
Zhengda Lu, Dakota O’Dell, Balaji Srinivasan, Elizabeth Rey, Ruisheng Wang, Sasank Vemulapati, Saurabh Mehta, David Erickson

[link url="http://mediarelations.cornell.edu/2017/12/05/new-quick-portable-test-for-iron-vitamin-a-deficiency-could-help-save-lives-around-the-world/"]Cornell University material[/link]
[link url="http://www.pnas.org/content/early/2017/11/28/1711464114"]Proceedings of the National Academy of Sciences abstract[/link]

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