Drug-Resistant Malaria - libdoc.who.int - World Health Organization

IV.
Monitoring of Drug Response of P. faiciparum
The main effort 1n the
currently centred on the
techniques are available for
vitro methods.
testing of antimalarial drugs is
blood schizontocidal drugs, and
assessing them by in vivo and 1n
The in vivo method assesses the results of a standard radical
cure treat.;;nt on plasmodial infections over a period of 7 days -
the WHO Standard Field Test, - or over a period of 28 days - the
WHO Extended Field Test. The standard test provides an assessment
of resistance at the RII and RIll levels; RI resistance can only
be detected with the extended 28-day test.
The development of an in vitro test system permits a .truly
objective assessment of the sensitivity of P.falci~~~~ to various
blood schizontocidal drugs. The in vitro test systems currently
available (all limited to P.falciparum) are: a macro culture
technique in which glucose supported defribinated blood samples
are incubated. at approximately 38 °c over 24 hours; a micro
culture technique using culture medium to support very small
quantities of heparinized patient-blood at similar incubation
condi t ions; and in_~it ro tes ts using mat erial from cont inuous
culture.
The macro in vitro technique is simple and relatively easy to
carry out unde0Ield conditions. The simplicity and long-term
dependability of the test may make its continued use desirable in
hospitals, for instance, where blood collection by venipuncture is
not a problem and when only a few tests are required during a year.