Challenges in routine implementation and quality control of rapid diagnostic tests for malaria--Rufiji District, Tanzania.
Rapid diagnostic tests (RDTs) represent an alternative to microscopy for malaria diagnosis and have shown high sensitivity and specificity in a variety of study settings. Current World Health Organization (WHO) guidelines for quality control of RDTs provide detailed instructions on pre-field testing, but offer little guidance for quality assurance once RDTs are deployed in health facilities. From September 2006 to April 2007, we introduced a histidine-rich protein II (HRP2)-based RDT (Paracheck) for suspected malaria cases five years of age and older in nine health facilities in Rufiji District, Tanzania, to assess sensitivity and specificity of RDTs in routine use at rural health facilities. Thick blood smears were collected for all patients tested with RDTs and stained and read by laboratory personnel in each facility. Thick smears were subsequently reviewed by a reference microscopist to determine RDT sensitivity and specificity. In all nine health facilities, there were significant problems with the quality of staining and microscopy. Sensitivity and specificity of RDTs were difficult to assess given the poor quality of routine blood smear staining. Mean operational sensitivity of RDTs based on reference microscopy was 64.8%, but varied greatly by health facility, range 18.8-85.9%. Sensitivity of RDTs increased with increasing parasite density. Specificity remained high at 87.8% despite relatively poor slide quality. Institution of quality control of RDTs based on poor quality blood smear staining may impede reliable measurement of sensitivity and specificity and undermine confidence in the new diagnostic. There is an urgent need for the development of alternative quality control procedures for rapid diagnostic tests that can be performed at the facility level.
McMorrow
Meredith L
ML
Malaria Branch, Division of Parasitic Diseases, National Center for Zoonotic Vector-borne and Enteric Diseases, US Centers for Disease Control and Prevention, USA. MMcmorrow@cdc.gov
Masanja
M Irene
MI
Abdulla
Salim M K
SM
Kahigwa
Elizeus
E
Kachur
S Patrick
SP
D000328:Adult; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D008288:Malaria / Q000175:diagnosis* / Q000453:epidemiology; D011786:Quality Control; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D012680:Sensitivity and Specificity; D013636:Tanzania / Q000453:epidemiology; D013997:Time Factors
D011933:Reagent Kits, Diagnostic
Trop Med Int Health. 2002 Jan;7(1):45-52
11851954
BMJ. 2007 Feb 24;334(7590):403
17259188
J Infect Dis. 2005 Sep 1;192(5):870-7
16088837
BMJ. 2004 Nov 20;329(7476):1212
15542534
Trop Med Int Health. 2001 Feb;6(2):99-101
11251904
Acta Trop. 2004 Apr;90(2):211-4
15177148
Trop Med Int Health. 2001 Jun;6(6):423-8
11422955
Parasitology. 1987 Oct;95 ( Pt 2):209-27
3320887
Clin Microbiol Rev. 2002 Jan;15(1):66-78
11781267
Trans R Soc Trop Med Hyg. 1993 Nov-Dec;87(6):662-5
8296367