ABSTRACT Biomarker qualification is a process whereby the analytical and clinical performance of a biomarker is tested to determine its suitability for a particular Context of Use (COU). Clinical trials of malaria drugs, vaccines, and other therapeutics benefits from high quality diagnostics, but many of the existing diagnostic modalities such as rapid diagnostic tests and thick blood smear microscopy are relatively insensitive and/or operator-dependent. In contrast, molecular diagnostic biomarker testing for Plasmodium falciparum has been shown to be analytically and clinically sensitive and specific in many settings. In this project, biomarker testing will be performed on archival samples from malaria endemic site clinical trials and the data will be utilized to support an expanded Context of Use for the Plasmodium falciparum 18S rRNA biomarker for malaria-endemic field studies.