Ab9203

Dynabeads® MyOneTM Streptavidin T1 beads were purchased from Life Technologies (Cat #65601). Recombinant P. falciparum lactate dehydrogenase (rcPfLDH) and recombinant Plasmodium vivax lactate dehydrogenase (rcPvLDH) were purchased from CTK Biotech (Cat #A3005, #A3004). P. falciparum D6 strain was cultured in the lab. P. falciparum W2, Benin 1, and PH1 reference strains were obtained from the Foundation for Innovative New Diagnostics (FIND). Anti-PfHRPII capture and detection antibodies were purchased from Abcam (ab9203 and ab30384). Pan-specific α-pLDH antibodies were purchased from AccessBio, Fitzgerald, and Vista Diagnostics (Table S1). BluePhos® Microwell Phosphatase substrate was purchased from KPL (#50-88-02), and TMB One was purchased from Promega (G7431). The ELISA kit for pLDH was purchased from SD Bioline, S. Korea (05EK40), and the ELISA kit for PfHRPII was purchased from Cellabs, Australia (KM2).

Anti-pLDH and anti-HRP2 beads were prepared as reported previously.^{19 (link),24 (link)} Briefly, anti-pLDH (Vista 19g7) or anti-HRP2 (Abcam ab9203) was biotinylated with EZ-Link NHS–PEG4–Biotin, No-Weigh Format (Thermo no. 21329). Unreacted NHS–PEG4–Biotin was removed using 7K MWCO Zebra spin desalting columns (Thermo no. 89882). Next, 5 mg of Dynabeads MyOne streptavidin T1 was washed three times with PBS and incubated with 500 μL of 0.4 mg/mL biotinylated antibody in PBS for 30 minutes. The beads were then washed before incubating in excess D-biotin in PBS for 30 minutes. Finally, the beads were washed and resuspended in 500 μL of PBS with 0.01% Tween-20. Stock solutions of antibody-functionalized beads were transported to Zambia in ambient conditions and stored at 4°C on arrival.

Human whole blood (CPD) was purchased from Bioreclamation IVT (catalog no. HMWBCPD). Recombinant HRP2 protein (rcHRP2) was generously provided by PATH (Seattle, WA). Plasmodium falciparum D6 strain was cultured in-house. Dynabeads^® Protein A, Dynabeads^® Protein G, and Pierce Protein L Magnetic Particles were purchased from Fisher Scientific (10-002-D, 10-004-D, PI88850). Anti-HRP2 antibodies were purchased from Abcam (ab9203, ab9206, ab30384). TMB One was purchased from Promega (G7431). 903 Protein Saver Cards were purchased from GE Healthcare Life Sciences (10534612). A Fisher Scientific Analog Vortex Mixer (02-215-365) was used for all vortexed incubations. A VWR Digital Dry Heatblock (12621-086) with an external thermocouple (11301-112) was used for sample heating. Absorbance was measured on a Biotek Synergy H4 microplate reader (Vanderbilt University) or Biotek ELx808 microplate reader (Macha Research Trust). All other reagents and materials were purchased from either Fisher Scientific or Sigma Aldrich.