Validity and reliability of methods to microscopically detect and quantify malaria parasitaemia
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Validity and reliability of methods to microscopically detect and quantify malaria parasitaemia. / Mischlinger, Johannes; Pitzinger, Paul; Veletzky, Luzia; Groger, Mirjam; Zoleko-Manego, Rella; Adegnika, Ayola A; Agnandji, Selidji T; Lell, Bertrand; Kremsner, Peter G; Mombo-Ngoma, Ghyslain; Mordmüller, Benjamin; Ramharter, Michael.
in: TROP MED INT HEALTH, Jahrgang 23, Nr. 9, 09.2018, S. 980-991.Publikationen: SCORING: Beitrag in Fachzeitschrift/Zeitung › SCORING: Zeitschriftenaufsatz › Forschung › Begutachtung
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TY - JOUR
T1 - Validity and reliability of methods to microscopically detect and quantify malaria parasitaemia
AU - Mischlinger, Johannes
AU - Pitzinger, Paul
AU - Veletzky, Luzia
AU - Groger, Mirjam
AU - Zoleko-Manego, Rella
AU - Adegnika, Ayola A
AU - Agnandji, Selidji T
AU - Lell, Bertrand
AU - Kremsner, Peter G
AU - Mombo-Ngoma, Ghyslain
AU - Mordmüller, Benjamin
AU - Ramharter, Michael
N1 - © 2018 John Wiley & Sons Ltd.
PY - 2018/9
Y1 - 2018/9
N2 - 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.
AB - 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.
KW - Journal Article
U2 - 10.1111/tmi.13124
DO - 10.1111/tmi.13124
M3 - SCORING: Journal article
C2 - 29956431
VL - 23
SP - 980
EP - 991
JO - TROP MED INT HEALTH
JF - TROP MED INT HEALTH
SN - 1360-2276
IS - 9
ER -