Rapid diagnostic testing platform for iron and vitamin A deficiency

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.

Improving the limit of detection in portable luminescent assay readers through smart optical design

“…For example, many of these reports include readers using low‐cost components, typically involving a mobile phone, mobile phones and other portable sensors (such as the popular Raspberry Pi camera platform). These low‐cost consumer‐grade optoelectronics have been explored as convenient platform for biomedical testing devices for several years, including microscopes , spectrometers , assay readers , among other uses . Due to their incorporation of on‐board computing, intuitive interfaces, wireless communication and relatively high quality imaging sensors, their attractiveness as the basis of a sensing platform is undeniable.…”

Fluorescence lateral flow competitive protein binding assay for the assessment of serum folate concentrations

“…To determine the signal from this fluorescent lateral flow strip, we used a portable imaging device designed previously by our lab. This device was described previously by Lu et al[31]. Briefly, it consists of a Raspberry Pi computer board, a 5-megapixel CMOS camera, a lithium-ion battery, blue LEDs, fluorescence and focusing optics, and a light-tight 3D-printed case with a tray for the lateral flow strip cassette.…”

Portable Multiplex Optical Assays

“…Reprinted from refs. (a), (b), (c), (d), (e), (f), (g), (h), and (i) with permission: Copyright 2012, Elsevier Ltd. (a); Copyright 2012 and 2011, The Royal Society of Chemistry (b and g); CC‐BY 4.0 open access publication (c and f); CC‐BY‐NC‐ND 4.0 open access publication (d); ACS AuthorChoice License open access publication (e); Copyright 2006, Springer Science Business Media (h); Copyright 2014, American Chemical Society (i).…”

“…Another multiplexed lateral flow assay was developed based on fluorescent reporters (Figure D). Three target proteins in the blood serum, ferritin, retinol‐binding protein (RBP), and C reactive protein (CRP), were detected by a multicolor test strip to monitor iron and vitamin A deficiency . Similar to the cellphone‐based integrated reader, this multiplex nutrition sensing platform was analyzed by a smartphone interface.…”