Table 1.

Pros and cons of five markers of artemisinin resistance.

	Therapeutic efficacy of ACT	Proportion of cases microscopy positive at day 3	Parasite clearance half-life	Ring-stage survival assay (RSA)	K13 sequencing
Influence on antimalarial policy	Direct	Indirect	Indirect	Indirect	Indirect
Confounded by partner drug	Yes	Yes	In theorya	No	No
Confounded by starting parasitaemia	Yes	Yes	Slightlyb	No	No
Level of assessment	Population	Population	Individual	Individual	Individual
Convenient for patient	Requires at least 42 days follow-up	Minimal follow-up required	Requires frequent sampling for 2–3 days	Yes	Yes
Specific resources required	PCR differentiation for recurrences	None	Inpatient stay, accurate parasite quantification	Expertise, culture facilities	Access to sequencing

^aNo direct evidence, but theoretically possible given the influence of partner drug on day 3 positivity (Stepniewska et al.2010).

^bIn areas of artemisinin resistance, high parasitaemias were associated with slightly longer PC_1/2 (by 5.2% per 10-fold increase) (WWARN Parasite Clearance Study Group 2015).