An inexpensive experimental test that detects levels of an HIV protein in the blood is as effective in predicting early-stage HIV disease progression as such standard tests that determine blood-based viral loads and T-cell counts, according to a study in the October 15 edition of the Journal of Infectious Diseases. Timothy Sterling of the Johns Hopkins University School of Medicine and his colleagues compared the effectiveness of an experimental test that measures blood-based levels of HIV's p24 antigen protein with T-cell and viral load tests among 494 injection-drug users who had recently been infected with HIV. The five-year study showed that the antigen test was comparable to the other tests at predicting AIDS progression. The test has been previously studied and used to project disease progression among those with late-stage infections or who have been diagnosed with AIDS. Because the antigen tests cost between $20 and $30, compared with an average cost of about $100 for tests that detect T-cell levels and over $150 for tests that scan for blood-based viral loads, researchers say it may be widely used in developing nations to help track early-stage HIV patients.