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All that is blood is not schistosomiasis: experiences with reagent strip testing for urogenital schistosomiasis with special consideration to very-low prevalence settings.

Krauth SJ, Greter H, Stete K, Coulibaly JT, Traoré SI, Ngandolo BN, Achi LY, Zinsstag J, N'Goran EK, Utzinger J - Parasit Vectors (2015)

Bottom Line: Kappa agreement and regression models were employed to compare data for different S. haematobium prevalence categories.We found a "background" prevalence of microhaematuria (13 %, on average) which does not seem to be associated with schistosomiasis in most settings, irrespective of the prevalence of S. haematobium.Our findings underscore the need for highly accurate diagnostic tools for settings targeted for elimination of urogenital schistosomiasis.

View Article: PubMed Central - PubMed

Affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland. stefanie.krauth@unibas.ch.

ABSTRACT

Background: Reagent strip testing for microhaematuria has long been used for community diagnosis of Schistosoma haematobium. Sensitivities and specificities are reasonable, and hence, microhaematuria can serve as a proxy for S. haematobium infection. However, assessment of test performance in the context of the underlying S. haematobium prevalence is rare and test parameters other than sensitivity and specificity have been neglected.

Methods: Data about the association between microhaematuria and urine filtration results from three studies were compared and put into context with findings from a recent Cochrane review. Data were stratified by S. haematobium prevalence to identify prevalence-related differences in test performance. Kappa agreement and regression models were employed to compare data for different S. haematobium prevalence categories.

Results: We found a "background" prevalence of microhaematuria (13 %, on average) which does not seem to be associated with schistosomiasis in most settings, irrespective of the prevalence of S. haematobium. This background level of microhaematuria might be due to cases missed with urine filtration, or alternative causes apart from S. haematobium. Especially in very-low prevalence settings, positive results for microhaematuria likely give an inaccurate picture of the extent of S. haematobium, whereas negative results are a sound indicator for the absence of infection.

Conclusions: Reagent strip testing for microhaematuria remains a good proxy for urogenital schistosomiasis, but implications of test results and scope of application differ depending on the setting in which reagent strips are employed. In very-low prevalence settings, microhaematuria is an unstable proxy for urogenital schistosomiasis and treatment decision should not be based on reagent strip test results alone. Our findings underscore the need for highly accurate diagnostic tools for settings targeted for elimination of urogenital schistosomiasis.

No MeSH data available.


Related in: MedlinePlus

Positive and negative predictive values over S. haematobium prevalence.
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Fig4: Positive and negative predictive values over S. haematobium prevalence.

Mentions: While sensitivity and specificity were relatively stable over various prevalence levels, PPV and NPV are inherently dependent on prevalence (Figs. 3 and 4). However, the percentage of microhaematuria seemingly unrelated to S. haematobium was stable over different prevalence ranges when taken into account that it will be hidden for higher prevalences.Fig. 3


All that is blood is not schistosomiasis: experiences with reagent strip testing for urogenital schistosomiasis with special consideration to very-low prevalence settings.

Krauth SJ, Greter H, Stete K, Coulibaly JT, Traoré SI, Ngandolo BN, Achi LY, Zinsstag J, N'Goran EK, Utzinger J - Parasit Vectors (2015)

Positive and negative predictive values over S. haematobium prevalence.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4641389&req=5

Fig4: Positive and negative predictive values over S. haematobium prevalence.
Mentions: While sensitivity and specificity were relatively stable over various prevalence levels, PPV and NPV are inherently dependent on prevalence (Figs. 3 and 4). However, the percentage of microhaematuria seemingly unrelated to S. haematobium was stable over different prevalence ranges when taken into account that it will be hidden for higher prevalences.Fig. 3

Bottom Line: Kappa agreement and regression models were employed to compare data for different S. haematobium prevalence categories.We found a "background" prevalence of microhaematuria (13 %, on average) which does not seem to be associated with schistosomiasis in most settings, irrespective of the prevalence of S. haematobium.Our findings underscore the need for highly accurate diagnostic tools for settings targeted for elimination of urogenital schistosomiasis.

View Article: PubMed Central - PubMed

Affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland. stefanie.krauth@unibas.ch.

ABSTRACT

Background: Reagent strip testing for microhaematuria has long been used for community diagnosis of Schistosoma haematobium. Sensitivities and specificities are reasonable, and hence, microhaematuria can serve as a proxy for S. haematobium infection. However, assessment of test performance in the context of the underlying S. haematobium prevalence is rare and test parameters other than sensitivity and specificity have been neglected.

Methods: Data about the association between microhaematuria and urine filtration results from three studies were compared and put into context with findings from a recent Cochrane review. Data were stratified by S. haematobium prevalence to identify prevalence-related differences in test performance. Kappa agreement and regression models were employed to compare data for different S. haematobium prevalence categories.

Results: We found a "background" prevalence of microhaematuria (13 %, on average) which does not seem to be associated with schistosomiasis in most settings, irrespective of the prevalence of S. haematobium. This background level of microhaematuria might be due to cases missed with urine filtration, or alternative causes apart from S. haematobium. Especially in very-low prevalence settings, positive results for microhaematuria likely give an inaccurate picture of the extent of S. haematobium, whereas negative results are a sound indicator for the absence of infection.

Conclusions: Reagent strip testing for microhaematuria remains a good proxy for urogenital schistosomiasis, but implications of test results and scope of application differ depending on the setting in which reagent strips are employed. In very-low prevalence settings, microhaematuria is an unstable proxy for urogenital schistosomiasis and treatment decision should not be based on reagent strip test results alone. Our findings underscore the need for highly accurate diagnostic tools for settings targeted for elimination of urogenital schistosomiasis.

No MeSH data available.


Related in: MedlinePlus