Worldwide, pneumonia is one of the leading causes of mortality in children in the first 5 years of life. In both developed countries and resource poor settings, detection of bacterial pathogens by culturing blood or other specimens is time consuming, lacks sensitivity and ranges from difficult in the U.S. to impossible in the developing world. In the U.S., the inability to determine which children have a bacterial infection results in excessive use of antibiotics and increased risk of infection with multi-drug resistant organisms. In the developing world, the consequences are delays in timely initiation of antibiotic therapy and excessive referral of children for hospitalization that overwhelms referral facilities. Regardless of setting, there is an urgent need for point of care diagnostics to determine which children likely have bacterial pneumonia and will benefit from administration of antibiotics.