Describing the development of an automated digital immunoassay for p24, a capsid protein of the human immunodeficiency virus (HIV), a recent study of the Simoa technology by Quanterix Corp, Lexington, Mass, demonstrates the analytical and clinical efficacy of the test by measuring HIV in the earliest infections detectable by nucleic acid testing (NAT).1

While NAT has become the highsensitivity standard for detecting low levels of the virus, adoption of NAT can be cost prohibitive in low-resource settings. With the Simoa technology, researchers found a low-cost, fully automated digital p24 antigen immunoassay with the sensitivity of quantitative NAT viral load methods for the detection of acute HIV infection. The digital immunoassay exhibited >4000-fold greater sensitivity than contemporary immunoassays for p24, and sensitivity equivalent to that of NAT methods for early detection of HIV.

Michael P. Busch, MD, PhD, Blood Systems Inc.

Michael P. Busch, MD, PhD, Blood Systems Inc.

“It is very exciting to see such impressive results with an immunoassay for HIV p24 Ag, with the Simoa digital immunoassay exhibiting the sensitivity of state-of-the-art viral load assays and approaching the sensitivity of blood screening NAT assays,” says Michael P. Busch, MD, PhD, co-director of the Blood Systems Research Institute San Francisco, and senior vice president of research and scientific affairs at Blood Systems Inc, Scottsdale, Ariz. “I am encouraged by the potential of Simoa and look forward to further evaluating the utility of this and other next-generation immunoassays from Quanterix for diagnostic and blood screening applications.”

Photo Hrusovsky Kevin

Kevin Hrusovsky, Quanterix.

“This study is a significant advancement in early detection and treatment of infectious disease,” says Kevin Hrusovsky, CEO and executive chairman of Quanterix. “The unique sensitivity of our technology to detect acute HIV infection early on can help limit the spread of the disease by offering a rapid, accurate, and low-cost alternative to existing tools. We’re excited about the possibilities associated with Simoa to detect acute infectious disease and hope to eventually transform today’s sick care to true, preventative healthcare through these advanced detection screenings.”

For more information, visit Quanterix.


  1. Cabrera C, Chang L, Stone M, et al. Rapid, fully automated digital immunoassay for p24 protein with the sensitivity of nucleic acid amplification for detecting acute HIV infection. Clin Chem. 2015;61(11):1372–1380; doi: 10.1373/clinchem.2015.243287.