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RBP-EIA test for vitamin A deficiency.

This new test will allow more countries to identify communities in need of vitamin A.

A new diagnostic tool measures deficiency at the population level

A new test developed by PATH is helping assess a nutritional deficiency common to the developing world—one that can cause blindness, severe illness, and death if uncorrected. More than 100 million children worldwide get too little vitamin A, most of them in places where few families have access to fresh foods (certain fruits, vegetables, and meat and eggs). PATH’s test will give developing countries a way to identify vulnerable populations—so that they can use limited public health resources as effectively as possible.

Revealing a hidden indicator

The first step to solving public health problems is accurate assessment. The tests that are currently used to assess vitamin A deficiency, however, are expensive and complex—not appropriate in countries where money is tight, training is basic, and cutting-edge laboratory equipment is rare.

The standard way to identify vitamin A deficiency is to measure levels of retinol (pure vitamin A) in the blood. The testing process requires expensive laboratory equipment with skilled staff, both in short supply in countries where vitamin A deficiency is most severe. PATH’s test instead measures retinol-binding protein—an indicator of the amount of vitamin A in the blood that can be measured using simple diagnostic procedures requiring limited technical skill and equipment. Our test, the “RBP-EIA” (retinol-binding protein-enzyme immunoassay):

  • Can be carried out using standard laboratory equipment.
  • Requires only a small blood sample of either venous blood or capillary blood, which can be collected through a simple finger stick.
  • Yields results in less than 40 minutes, vastly reducing the time between collecting samples and getting results.

In the market for child survival

To help get the test to commercial markets more quickly, PATH has licensed the technology to Scimedx, a United States–based diagnostics company with the experience to bring the product quickly to the market. PATH and Scimedx are working closely with public health officials in developing countries to train technical and health care workers in using the test—preparing systems that will allow it to fall easily into place.

The RBI-EIA will make assessing vitamin A deficiency easier and cheaper in countries that already do so. But the real impact will be felt in countries that don’t have the resources to use current methods to measure prevalence in their populations. For those countries, the test offers a new opportunity to build programs based on accurate information and to maximize use of limited resources to control vitamin A deficiency.

Photo: PATH.