DNA-targeting test promises to simplify and accelerate HIV diagnosis

The current gold standard to diagnose HIV in infants and to monitor viral load depends on lab equipment and technical expertise generally available only in clinics, said Rice bioengineer Rebecca Richards-Kortum. The new research features a nucleic acid-based test that can be performed at the site of care.

Richards-Kortum, director of the Rice 360˚: Institute for Global Health Technologies, and her colleagues reported their results in the American Chemical Society journal Analytical Chemistry.

The proof-of-concept work by co-lead authors Zachary Crannell and Brittany Rohrman, both graduate students in the Richards-Kortum lab, follows their similar technique to detect the parasite that causes the diarrheal disease cryptosporidiosis.

The new technique would replace a complex lab procedure based on polymerase chain reaction with one that relies on recombinase polymerase amplification (RPA), a method to quickly amplify genetic markers found in blood to levels where they can be easily counted.

In a test the team calls qRPA, a specific sequence in HIV DNA is targeted and tagged with fluorescent probes that can be seen and quantified by a portable machine. Software analysis of the fluorescing DNA allows clinicians to determine with whether the virus is present in a patient’s blood and/or how much is there.