Microfluidic diagnostic technologies for global public health.

The developing world does not have access to many of the best medical diagnostic technologies; they were designed for air-conditioned laboratories, refrigerated storage of chemicals, a constant supply of calibrators and reagents, stable electrical power, highly trained personnel and rapid transportation of samples. Microfluidic systems allow miniaturization and integration of complex functions, which could move sophisticated diagnostic tools out of the developed-world laboratory. These systems must be inexpensive, but also accurate, reliable, rugged and well suited to the medical and social contexts of the developing world.

Development of a rapid enzyme immunoassay for the detection of retinol-binding protein.

Background: Retinol-binding protein (RBP) was chosen as a surrogate marker for retinol because of the close correspondence between retinol and RBP.

Objective: To meet the need for rapid, cost-effective determination of vitamin A status in populations, a quantitative enzyme immunoassay (EIA) for detection of RBP was developed.

Design: The resulting RBP EIA, a competitive assay, uses RBP adsorbed to microtest strip wells to compete with RBP in serum.

Development of a rapid immunodiagnostic test for Haemophilus ducreyi.

Haemophilus ducreyi is the etiologic agent of chancroid, a sexually transmitted disease that increases the rate of transmission of human immunodeficiency virus. Chancroid ulcerations are difficult to distinguish from those produced by syphilis and herpes. Diagnosis based solely on clinical grounds is inaccurate, and culture is insensitive.

Preliminary evaluation of an immunochromatographic strip test for specific Treponema pallidum antibodies.

We evaluated a prototype immunochromatographic strip (ICS) test for qualitative detection of Treponema pallidum antibodies in 353 sera from 157 patients. For sera from 43 syphilis patients, the ICSs were reactive, while for sera from 114 patients without syphilis, including 22 with biologically false-positive Rapid Plasma Reagin test results, the ICSs were nonreactive. The ICS test may expand the available options for serological testing for syphilis.