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World’s first lateral flow assay for Histoplasma antigen launched

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In a ground-breaking development for patients with AIDS, the world’s first lateral flow assay able to detect Histoplasma antigen has been launched by MiraVista Diagnostics, based in Indianapolis, USA.

Diego Cáceres and colleagues at the Centers for Disease Control and Prevention (CDC) independently evaluated the new LFA in serum samples from patients and controls in Medellin, Colombia. There were 24 positives from patients with culture-proven disseminated histoplasmosis in AIDS and 51 controls with other infections diseases complicating AIDS. The assay detects H. capsulatum galactomannan antigen. When the LFA was read manually, sensitivity was 96% and specificity was 90%.

Sera were pretreated with EDTA and boiled and analysed with the LFA. The LFA process takes 30 minutes to read. The five false-positive results were from paracoccidioidomycosis, salmonellosis and for uncertain reasons. There was one false negative.  

It will be important to assess the LFA in patients’ urine and in patients who are culture-negative but have other manifestations of disseminated histoplasmosis. Two other LFA tests for Histoplasma antigen are in development and head to head comparisons will be valuable in the future.

Link to assay
Link to paper

Another reference test is also available as a service for specimens submitted (Miravista Labs) and this assay performs well, with well-characterised specimens. Antigenuria was detected in 92% of those with disseminated histoplasmosis and antigenemia in 100%. Those with severe disease and immunocompromised patients are more often positive. Lower frequencies of positivity are found in those with acute, subacute and chronic pulmonary histoplasmosis. Cross-reactivity was common in patients with blastomycosis.
A recent publication has evaluated the MiraVista EIA tests.

The first LFA assay has been released by MiraVista with an excellent performance in serum samples from culture-positive cases of disseminated histoplasmosis in AIDS. Additional data on urine samples is required.