Table 1.

Glossary of commonly used terms related to antimalarial efficacy monitoring

Term	Related terms	Definition
TES	In vivo study, therapeutic efficacy trial, and antimalarial efficacy trial	Clinical outcome trial to assess antimalarial efficacy in patients with malaria
Recurrent parasitemia	Late recurrence and late treatment failure*	Recurrence of microscopy-detectable parasitemia during follow-up despite initial clearance, typically defined as occurring 7 days or longer after initiation of therapy
New infection	Reinfection	Recurrent parasitemia due to a new infection with a parasite strain/clone different from the strain/clone from the original infection
Recrudescence	True treatment failure	Recurrent parasitemia due to inadequate clearance of a parasite strain/clone from the original infection
Locus	Marker and gene	A polymorphic site or region in the parasite genome that can be used to differentiate between different parasite strains
Allele	Band and haplotype	A distinct variant of a given locus; even though Plasmodium is haploid in the human host, multiple alleles can be observed in a given sample due to a multi-clone infection (concurrent infection by more than one strain)
Molecular correction	PCR correction	Process by which cases of recurrent parasitemia are classified as new infections or recrudescences by comparison of parasite genotypes
PCR-corrected efficacy	Corrected efficacy	Primary indicator from TESs, where only recrudescent infections are counted as treatment failures and reinfections are excluded or censored

TESs = therapeutic efficacy studies.

^*“Recurrent parasitemia” and “late recurrence” are preferable terms to “late treatment failure” because they unambiguously encompass both recrudescences and new infections.