WHO procurement service for diagnostics: http://www.who.int/
Global Fund: Procurement of quality-assured diagnostics: [link to PDF]
WHO Prequalification of Diagnostics Programme: http://www.who.int/
Global Drug Facility (including diagnostics): http://www.stoptb.org/gdf/
Global Fund: Quality Assurance of Diagnostic Products http://www.theglobalfund.org/