Validity and reliability of methods to microscopically detect and quantify malaria parasitaemia.
Trop Med Int Health
; 23(9): 980-991, 2018 09.
Article
en En
| MEDLINE
| ID: mdl-29956431
ABSTRACT
OBJECTIVES:
The recommended microscopy method by WHO to quantify malaria parasitaemia yields inaccurate results when individual leucocyte (WBC) counts deviate from 8000 leucocytes/µl. A method avoiding WBC count assumptions is the Lambaréné method (LAMBA). Thus, this study compared validity and reliability of the LAMBA and the WHO method.METHODS:
Three methods for counting parasitaemia were applied in parallel in a blinded assessment the LAMBA, the WHO method using a standard factor of 8000 leucocytes/µl ['simple WHO method' (sWHO)] and the WHO method using measured WBC counts ['accurate WHO method' (aWHO)]. Validity was assessed by comparing LAMBA and sWHO to the gold standard measurement of aWHO. Reliability was ascertained by computation of intraclass correlation coefficients (ICCs).RESULTS:
787 malaria-positive thick smears were analysed. Parasitaemia as determined by LAMBA and sWHO increasingly deviated from aWHO the more patients' WBCs diverged from 8000/µl. Equations of linear regression models assessing method deviation in percent from gold standard as function of WBC count were y = -0.00608x (95% CI -0.00693 to -0.00524) + 47.8 for LAMBA and y = -0.0125x (95% CI -0.01253 to -0.01247) + 100.1 for sWHO. Comparison of regression slopes showed that the deviation was twice as high for sWHO as for LAMBA (P < 0.001). ICCs were excellent (>90%) for both methods.CONCLUSIONS:
The LAMBA has higher validity than the sWHO and may therefore be preferable in resource-limited settings without access to routine WBC-evaluation.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Parasitemia
/
Malaria
/
Microscopía
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Trop Med Int Health
Asunto de la revista:
MEDICINA TROPICAL
/
SAUDE PUBLICA
Año:
2018
Tipo del documento:
Article
País de afiliación:
Austria