Differentiating pLDH orthologs. A. Test strips with the indicated immobilized antibodies were reacted with recombinant Pf-LDH, Pm-LDH, Po-LDH or Pv-LDH and visualized with 6C9-conjugated colloidal gold. A goat anti-mouse line is also indicated (Cont). A 1:100 dilution of enzyme (~ 10% parasitaemia) was used. B. A dilution series (1:10) of Pf-LDH and Pm-LDH was reacted with test strip containing immobilized 7E7 and 17E4 antibodies. The starting concentration of enzyme approximates a blood sample of 10% parasitaemia. C. Example of a Pf/non-Pf test format that can detect all four species of human malaria and distinguish Pf-LDH from the other species. Test strips contained immobilized 20G7 and 7G9 antibodies as well as a control (Cont) goat anti-mouse line. Reactions were visualized with gold conjugated to 2B5. A 1:100 dilution of the enzyme (~10% parasitaemia) stocks was used for the samples. D. The same 20G7-7G9 strip used in C was used to detect Pf-LDH using 19G7-conjugated colloidal gold. E. Similar assay format as shown in C except with the addition of an immobilized stripe of Pv-specific 13H1 antibody. F. Alternative Pf/non-Pf test format. Test strips containing immobilized 7G9 and 9C1 were reacted with pLDH from the indicated species. Reaction bands were visualized with colloidal gold conjugated to either 6C9, 12G1, 14C2 or 15F10 as indicated.