Utility of the detection of <it>Plasmodium </it>parasites for the diagnosis of malaria in endemic areas
<p>Abstract</p> <p>Background</p> <p>In populations where the prevalence of infection with <it>Plasmodium </it>parasites is high, blood tests that identify <it>Plasmodium </it>parasites in patients with fever may lead to false positive diagnosis...
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| Format: | Article |
| Language: | English |
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BMC
2006-05-01
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| Series: | BMC Infectious Diseases |
| Online Access: | http://www.biomedcentral.com/1471-2334/6/81 |
| _version_ | 1818272217506512896 |
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| author | Szeless Thomas Perneger Thomas V Rougemont André |
| author_facet | Szeless Thomas Perneger Thomas V Rougemont André |
| author_sort | Szeless Thomas |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>In populations where the prevalence of infection with <it>Plasmodium </it>parasites is high, blood tests that identify <it>Plasmodium </it>parasites in patients with fever may lead to false positive diagnosis of malaria-disease. We characterised the diminishing value of the parasite detection test as a function of the prevalence of infection.</p> <p>Methods</p> <p>We computed the ability of the parasite detection test to identify malaria at various levels of prevalence (0% to 90%), assuming plausible estimates of sensitivity (95% and 85%) and specificity (99% and 95%) for the detection of parasites. In each situation, we computed likelihood ratios of malaria (or absence of malaria) for positive and negative parasite detection tests. Likelihood ratios were classified as clinically useful (≥ 10), intermediate (5–10), or unhelpful (<5).</p> <p>Results</p> <p>Likelihood ratios of positive tests were strongly related to the prevalence of infection in the general population: a positive test was unhelpful when the prevalence was 20% or more, and useful only when prevalence was 5% or less. The sensitivity and specificity of the test had little influence on these results. Likelihood ratios of negative tests were clinically useful when prevalence was 70% or less, but only for high levels of sensitivity (95%). If sensitivity was low (85%), the negative test was at best of intermediate utility, and was unhelpful if the prevalence of asymptomatic infection exceeded 30%.</p> <p>Conclusion</p> <p>Identification of <it>Plasmodium </it>parasites supports a diagnosis of malaria only in areas where the prevalence of <it>Plasmodium </it>infection is low. Wherever this prevalence exceeds about 20%, a positive test is clinically unhelpful.</p> |
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| format | Article |
| id | doaj.art-d37b6e7621fa4f1f890f7f59020e6edb |
| institution | Directory Open Access Journal |
| issn | 1471-2334 |
| language | English |
| last_indexed | 2024-12-12T21:38:34Z |
| publishDate | 2006-05-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Infectious Diseases |
| spelling | doaj.art-d37b6e7621fa4f1f890f7f59020e6edb2022-12-22T00:11:08ZengBMCBMC Infectious Diseases1471-23342006-05-01618110.1186/1471-2334-6-81Utility of the detection of <it>Plasmodium </it>parasites for the diagnosis of malaria in endemic areasSzeless ThomasPerneger Thomas VRougemont André<p>Abstract</p> <p>Background</p> <p>In populations where the prevalence of infection with <it>Plasmodium </it>parasites is high, blood tests that identify <it>Plasmodium </it>parasites in patients with fever may lead to false positive diagnosis of malaria-disease. We characterised the diminishing value of the parasite detection test as a function of the prevalence of infection.</p> <p>Methods</p> <p>We computed the ability of the parasite detection test to identify malaria at various levels of prevalence (0% to 90%), assuming plausible estimates of sensitivity (95% and 85%) and specificity (99% and 95%) for the detection of parasites. In each situation, we computed likelihood ratios of malaria (or absence of malaria) for positive and negative parasite detection tests. Likelihood ratios were classified as clinically useful (≥ 10), intermediate (5–10), or unhelpful (<5).</p> <p>Results</p> <p>Likelihood ratios of positive tests were strongly related to the prevalence of infection in the general population: a positive test was unhelpful when the prevalence was 20% or more, and useful only when prevalence was 5% or less. The sensitivity and specificity of the test had little influence on these results. Likelihood ratios of negative tests were clinically useful when prevalence was 70% or less, but only for high levels of sensitivity (95%). If sensitivity was low (85%), the negative test was at best of intermediate utility, and was unhelpful if the prevalence of asymptomatic infection exceeded 30%.</p> <p>Conclusion</p> <p>Identification of <it>Plasmodium </it>parasites supports a diagnosis of malaria only in areas where the prevalence of <it>Plasmodium </it>infection is low. Wherever this prevalence exceeds about 20%, a positive test is clinically unhelpful.</p>http://www.biomedcentral.com/1471-2334/6/81 |
| spellingShingle | Szeless Thomas Perneger Thomas V Rougemont André Utility of the detection of <it>Plasmodium </it>parasites for the diagnosis of malaria in endemic areas BMC Infectious Diseases |
| title | Utility of the detection of <it>Plasmodium </it>parasites for the diagnosis of malaria in endemic areas |
| title_full | Utility of the detection of <it>Plasmodium </it>parasites for the diagnosis of malaria in endemic areas |
| title_fullStr | Utility of the detection of <it>Plasmodium </it>parasites for the diagnosis of malaria in endemic areas |
| title_full_unstemmed | Utility of the detection of <it>Plasmodium </it>parasites for the diagnosis of malaria in endemic areas |
| title_short | Utility of the detection of <it>Plasmodium </it>parasites for the diagnosis of malaria in endemic areas |
| title_sort | utility of the detection of it plasmodium it parasites for the diagnosis of malaria in endemic areas |
| url | http://www.biomedcentral.com/1471-2334/6/81 |
| work_keys_str_mv | AT szelessthomas utilityofthedetectionofitplasmodiumitparasitesforthediagnosisofmalariainendemicareas AT pernegerthomasv utilityofthedetectionofitplasmodiumitparasitesforthediagnosisofmalariainendemicareas AT rougemontandre utilityofthedetectionofitplasmodiumitparasitesforthediagnosisofmalariainendemicareas |