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| ==Laboratory Findings== | | ==Laboratory Findings== |
| ===Peripheral Blood Smear===
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| [[Image:Malaria 0001.jpg|thumb|350px|left|Malaria]]
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| * The most economic, preferred, and reliable diagnosis of malaria is microscopic examination of [[blood film]]s because each of the four major parasite species has distinguishing characteristics.
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| * Two sorts of blood film are traditionally used.
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| ** Thin films are similar to usual blood films and allow species identification because the parasite's appearance is best preserved in this preparation.
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| ** Thick films allow the microscopist to screen a larger volume of blood and are about eleven times more sensitive than the thin film, so picking up low levels of infection is easier on the thick film, but the appearance of the parasite is much more distorted and therefore distinguishing between the different species can be much more difficult.
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| ** With the pros and cons of both thick and thin smears taken into consideration, it is imperative to utilize both smears while attempting to make a definitive diagnosis.<ref name="warhurst1996">{{cite journal | author=Warhurst DC, Williams JE | title=Laboratory diagnosis of malaria | journal=J Clin Pathol | year=1996 | volume=49 | pages=533–38 |id=PMID 8813948}}</ref>
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| ** From the thick film, an experienced microscopist can detect parasite levels (or [[parasitemia]]) down to as low as 0.0000001% of red blood cells. * Microscopic diagnosis can be difficult because the early trophozoites ("ring form") of all four species look identical and it is never possible to diagnose species on the basis of a single ring form; species identification is always based on several trophozoites. Please refer to the articles on each parasite for their microscopic appearances: ''[[Plasmodium falciparum|P. falciparum]], [[Plasmodium vivax|P. vivax]], [[Plasmodium ovale|P. ovale]], [[Plasmodium malariae|P. malariae]]''.
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| ===Antigen Detection Tests=== | | <!-- |
| * In areas where microscopy is not available, or where laboratory staff are not experienced at malaria diagnosis, there are [[Malaria antigen detection tests|antigen detection tests]] that require only a drop of blood.<ref>{{cite journal | author=Pattanasin S, Proux S, Chompasuk D, Luwiradaj K, Jacquier P, Looareesuwan S, Nosten F | title=Evaluation of a new Plasmodium lactate dehydrogenase assay (OptiMAL-IT®) for the detection of malaria | journal=Transact Royal Soc Trop Med | year=2003 | volume=97 | pages=672–4 | id=PMID 16117960}}</ref>
| | ==Laboratory Findings== |
| * OptiMAL-IT® will reliably detect ''falciparum'' down to 0.01% [[parasitemia]] and non-''falciparum'' down to 0.1%. ''Para''check-Pf® will detect parasitemias down to 0.002% but will not distinguish between ''falciparum'' and non-''falciparum'' malaria.
| | The table below displays the nonspecific laboratory abnormalities associated with Ebola infection, including:<ref name="pmid21084112">{{cite journal| author=Feldmann H, Geisbert TW| title=Ebola haemorrhagic fever. | journal=Lancet | year= 2011 | volume= 377 | issue= 9768 | pages= 849-62 | pmid=21084112 | doi=10.1016/S0140-6736(10)60667-8 | pmc=PMC3406178 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21084112 }} </ref> |
| | {| style="border: 2px solid #DCDCDC; font-size: 90%; width: 30%;" |
| | |+ '''Laboratory findings''' |
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| | ! style="width: 75px; background: #4479BA; text-align: center;"|{{fontcolor|#FFF|Test}} |
| | ! style="width: 200px; background: #4479BA; text-align: center;"| {{fontcolor|#FFF|Findings}} |
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| | | style="background: #F5F5F5; padding: 5px; text-align: center;"| '''[[White blood cell]] count''' |
| | | style="background: #DCDCDC; padding: 5px;"| [[Leucopenia]]<br>[[Lymphopenia]]<br>[[Neutrophilia]] |
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| | | style="background: #F5F5F5; padding: 5px; text-align: center;"| '''[[Blood smear]]''' |
| | | style="background: #DCDCDC; padding: 5px;"| [[Left shift]]<br>Atypical [[lymphocytes]] |
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| | | style="background: #F5F5F5; padding: 5px; text-align: center;"| '''[[Coagulation]]''' |
| | | style="background: #DCDCDC; padding: 5px;"| Consumption of [[clotting factors]]<br>Increased concentrations of [[fibrin degradation products]]<br> |
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| | | style="background: #F5F5F5; padding: 5px; text-align: center;"| '''[[Liver function tests]]''' |
| | | style="background: #DCDCDC; padding: 5px;"| Raised [[aspartate aminotransferase]]<br>Raised [[alanine aminotransferase]]<br>Extended [[prothrombin time]]<br>Extended [[partial thromboplastin time]] |
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| | | style="background: #F5F5F5; padding: 5px; text-align: center;"| '''[[Proteins]]''' |
| | | style="background: #DCDCDC; padding: 5px;"| [[Hyperproteinemia]] |
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| | | style="background: #F5F5F5; padding: 5px; text-align: center;"| '''[[Urinalysis]]''' |
| | | style="background: #DCDCDC; padding: 5px;"| [[Proteinuria]] |
| | |} |
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| ===Polymerase Chain Reaction===
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| * Parasite nucleic acids are detected using [[polymerase chain reaction]]. This technique is more accurate than microscopy. However, it is expensive, and requires a specialized laboratory.
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| * Moreover, levels of parasitemia are not necessarily correlative with the progression of disease, particularly when the parasite is able to adhere to blood vessel walls.
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| * Therefore more sensitive, low-tech diagnosis tools need to be developed in order to detect low levels of parasitaemia in the field. Areas that cannot afford even simple laboratory diagnostic tests often use only a history of subjective fever as the indication to treat for malaria.
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| * Molecular methods are available in some clinical laboratories and rapid real-time assays (for example, [[Real-time polymerase chain reaction|QT-NASBA]] based on the polymerase chain reaction)<ref>{{cite journal | title=Detection and identification of human Plasmodium species with real-time quantitative nucleic acid sequence-based amplification | author=Mens PF, Schoone GJ, Kager PA, Schallig HDFH. | journal=Malaria Journal | year=2006 | volume=5 | issue=80 | doi=10.1186/1475-2875-5-80 }}</ref> are being developed with the hope of being able to deploy them in endemic areas.
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| ===Geimsa Staining Technique===
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| * Using Giemsa-stained blood smears from children in Malawi, one study showed that unnecessary treatment for malaria was significantly decreased when clinical predictors (rectal temperature, nailbed pallor, and splenomegaly) were used as treatment indications, rather than the current national policy of using only a history of subjective fevers (sensitivity increased from 21% to 41%). <ref>{{cite journal |author=Redd S, Kazembe P, Luby S, Nwanyanwu O, Hightower A, Ziba C, Wirima J, Chitsulo L, Franco C, Olivar M |title=Clinical algorithm for treatment of Plasmodium falciparum malaria in children |journal=Lancet |volume=347 |issue=8996 |pages=223-7 |year=1996 |pmid=8551881}}.</ref>
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| Severe malaria is commonly misdiagnosed in Africa, leading to a failure to treat other life-threatening illnesses. In malaria-endemic areas, [[parasitemia]] does not ensure a diagnosis of severe malaria because parasitemia can be incidental to other concurrent disease. Recent investigations suggest that malarial [[retinopathy]] is better (collective sensitivity of 95% and specificity of 90%) than any other clinical or laboratory feature in distinguishing malarial from non-malarial [[coma]].<ref> Beare NA et al. ''Am J Trop Med Hyg.'' 2006 Nov;75(5):790-797.</ref>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Plasmodium falciparum 02.jpg|Blood smear from a ''P. falciparum'' [[Malaria culture|culture]] (K1 strain). Several red blood cells have ring stages inside them. Close to the center there is a schizont and on the left a trophozoite.
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| Image:Malaria2.jpg|Malaria (organisms in cells)
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| </gallery>
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| </div>
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| ===Electron Microscope===
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| [[Image:Malaria.jpg|thumb|left|250px|A ''Plasmodium'' sporozoite traverses the cytoplasm of a mosquito midgut epithelial cell in this false-color [[electron micrograph]].]]
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| ==References== | | ==References== |