Chagas disease laboratory findings: Difference between revisions
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__NOTOC__ | __NOTOC__ | ||
{{Chagas disease}} | {{Chagas disease}} | ||
{{CMG}} {{AE}} {{YD}} | |||
==Overview== | |||
Acute Chagas disease is often diagnosed by peripheral blood smear following the visual detection of ''T. cruzi'' parasite. Serology is often helpful for chronic cases, where positivity of both whole lysate and recombinant antigen assay is required for the diagnosis. Although PCR is sensitive in acute cases (e.g. exposure following organ transplantation), its sensitivity and specificity are variable in the chronic state and highly depend on the pre-test probability. | |||
==Laboratory Findings== | |||
===Blood smear=== | |||
*Acute Chagas disease is often diagnosed by visual detection of the ''T. cruzi'' parasite on peripheral blood smear. | |||
===Serology=== | |||
*Serology is not usually utilized in acute Chagas disease. | |||
*Detection of anti-trypanosomal IgG antibodies is helpful to detect chronic Chagas disease infections.<ref name="pmid22632639">{{cite journal| author=Rassi A, Rassi A, Marcondes de Rezende J| title=American trypanosomiasis (Chagas disease). | journal=Infect Dis Clin North Am | year= 2012 | volume= 26 | issue= 2 | pages= 275-91 | pmid=22632639 | doi=10.1016/j.idc.2012.03.002 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22632639 }} </ref><ref name="pmid18162039">{{cite journal| author=Tarleton RL, Reithinger R, Urbina JA, Kitron U, Gürtler RE| title=The challenges of Chagas Disease-- grim outlook or glimmer of hope. | journal=PLoS Med | year= 2007 | volume= 4 | issue= 12 | pages= e332 | pmid=18162039 | doi=10.1371/journal.pmed.0040332 | pmc=PMC2222930 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18162039 }} </ref> | |||
*A single assay for chronic ''T. cruzi'' infection is neither sensitive nor specific, and positive results from both whole parasite lysate and recombinant antigens are required to make the diagnosis of chronic Chagas disease.<ref name="pmid22632639">{{cite journal| author=Rassi A, Rassi A, Marcondes de Rezende J| title=American trypanosomiasis (Chagas disease). | journal=Infect Dis Clin North Am | year= 2012 | volume= 26 | issue= 2 | pages= 275-91 | pmid=22632639 | doi=10.1016/j.idc.2012.03.002 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22632639 }} </ref><ref name="pmid18162039">{{cite journal| author=Tarleton RL, Reithinger R, Urbina JA, Kitron U, Gürtler RE| title=The challenges of Chagas Disease-- grim outlook or glimmer of hope. | journal=PLoS Med | year= 2007 | volume= 4 | issue= 12 | pages= e332 | pmid=18162039 | doi=10.1371/journal.pmed.0040332 | pmc=PMC2222930 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18162039 }} </ref> | |||
*Detection of antibodies among infants may be difficult due to the presence of maternal antibodies early following birth. Accordingly, serologic testing for infants is only recommended at least 9 months after birth.<ref name="pmid21820550">{{cite journal| author=Bern C, Martin DL, Gilman RH| title=Acute and congenital Chagas disease. | journal=Adv Parasitol | year= 2011 | volume= 75 | issue= | pages= 19-47 | pmid=21820550 | doi=10.1016/B978-0-12-385863-4.00002-2 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21820550 }} </ref> | |||
===PCR=== | |||
*In acute disease, PCR is very sensitive and is widely used today to detect accidental exposure among organ transplant recipients following organ transplantation | |||
*In chronic disease, PCR sensitivity and specificity depend on the pre-test probability of Chagas disease.<ref name="pmid21264349">{{cite journal| author=Schijman AG, Bisio M, Orellana L, Sued M, Duffy T, Mejia Jaramillo AM et al.| title=International study to evaluate PCR methods for detection of Trypanosoma cruzi DNA in blood samples from Chagas disease patients. | journal=PLoS Negl Trop Dis | year= 2011 | volume= 5 | issue= 1 | pages= e931 | pmid=21264349 | doi=10.1371/journal.pntd.0000931 | pmc=PMC3019106 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21264349 }} </ref> | |||
*Serial PCR measurements are often necessary to confirm the diagnosis of Chagas disease.<ref name="pmid21264349">{{cite journal| author=Schijman AG, Bisio M, Orellana L, Sued M, Duffy T, Mejia Jaramillo AM et al.| title=International study to evaluate PCR methods for detection of Trypanosoma cruzi DNA in blood samples from Chagas disease patients. | journal=PLoS Negl Trop Dis | year= 2011 | volume= 5 | issue= 1 | pages= e931 | pmid=21264349 | doi=10.1371/journal.pntd.0000931 | pmc=PMC3019106 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21264349 }} </ref> | |||
*Quantitative PCR is helpful to monitor for Chagas reactivation, and increasing parasitic load on PCR is considered a sensitive surrogate of reactivation.<ref name="pmid19381287">{{cite journal| author=Duffy T, Bisio M, Altcheh J, Burgos JM, Diez M, Levin MJ et al.| title=Accurate real-time PCR strategy for monitoring bloodstream parasitic loads in chagas disease patients. | journal=PLoS Negl Trop Dis | year= 2009 | volume= 3 | issue= 4 | pages= e419 | pmid=19381287 | doi=10.1371/journal.pntd.0000419 | pmc=PMC2667272 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19381287 }} </ref> | |||
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==References== | ==References== | ||
{{Reflist|2}} | {{Reflist|2}} | ||
[[Category:Parasitic diseases]] | [[Category:Parasitic diseases]] | ||
[[Category:Zoonoses]] | [[Category:Zoonoses]] | ||
Revision as of 21:19, 5 August 2015
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Yazan Daaboul, M.D.
Overview
Acute Chagas disease is often diagnosed by peripheral blood smear following the visual detection of T. cruzi parasite. Serology is often helpful for chronic cases, where positivity of both whole lysate and recombinant antigen assay is required for the diagnosis. Although PCR is sensitive in acute cases (e.g. exposure following organ transplantation), its sensitivity and specificity are variable in the chronic state and highly depend on the pre-test probability.
Laboratory Findings
Blood smear
- Acute Chagas disease is often diagnosed by visual detection of the T. cruzi parasite on peripheral blood smear.
Serology
- Serology is not usually utilized in acute Chagas disease.
- Detection of anti-trypanosomal IgG antibodies is helpful to detect chronic Chagas disease infections.[1][2]
- A single assay for chronic T. cruzi infection is neither sensitive nor specific, and positive results from both whole parasite lysate and recombinant antigens are required to make the diagnosis of chronic Chagas disease.[1][2]
- Detection of antibodies among infants may be difficult due to the presence of maternal antibodies early following birth. Accordingly, serologic testing for infants is only recommended at least 9 months after birth.[3]
PCR
- In acute disease, PCR is very sensitive and is widely used today to detect accidental exposure among organ transplant recipients following organ transplantation
- In chronic disease, PCR sensitivity and specificity depend on the pre-test probability of Chagas disease.[4]
- Serial PCR measurements are often necessary to confirm the diagnosis of Chagas disease.[4]
- Quantitative PCR is helpful to monitor for Chagas reactivation, and increasing parasitic load on PCR is considered a sensitive surrogate of reactivation.[5]
-
![Trypanosoma cruzi in blood smear. From Public Health Image Library (PHIL). [6]](/images/9/9b/Chagas08.jpeg)
Trypanosoma cruzi in blood smear. From Public Health Image Library (PHIL). [6]
-
![Giemsa-stained micrograph shows a Trypanosoma cruzi protozoan parasite during its leishmanial stage of development. From Public Health Image Library (PHIL). [6]](/images/1/12/Chagas07.jpeg)
Giemsa-stained micrograph shows a Trypanosoma cruzi protozoan parasite during its leishmanial stage of development. From Public Health Image Library (PHIL). [6]
-
![Micrograph of Trypanosoma cruzi in a blood smear using Giemsa staining technique. From Public Health Image Library (PHIL). [6]](/images/3/36/Chagas05.jpeg)
Micrograph of Trypanosoma cruzi in a blood smear using Giemsa staining technique. From Public Health Image Library (PHIL). [6]
-
![Micrograph revealing Trypanosoma cruzi parasites in a blood smear using Giemsa staining technique (100x mag). From Public Health Image Library (PHIL). [6]](/images/a/a3/Chagas04.jpeg)
Micrograph revealing Trypanosoma cruzi parasites in a blood smear using Giemsa staining technique (100x mag). From Public Health Image Library (PHIL). [6]
![Trypanosoma cruzi in blood smear. From Public Health Image Library (PHIL). [6]](/index.php/File:Chagas08.jpeg)
![Giemsa-stained micrograph shows a Trypanosoma cruzi protozoan parasite during its leishmanial stage of development. From Public Health Image Library (PHIL). [6]](/index.php/File:Chagas07.jpeg)
![Micrograph of Trypanosoma cruzi in a blood smear using Giemsa staining technique. From Public Health Image Library (PHIL). [6]](/index.php/File:Chagas05.jpeg)
![Micrograph revealing Trypanosoma cruzi parasites in a blood smear using Giemsa staining technique (100x mag). From Public Health Image Library (PHIL). [6]](/index.php/File:Chagas04.jpeg)
References
- ↑ 1.0 1.1 Rassi A, Rassi A, Marcondes de Rezende J (2012). "American trypanosomiasis (Chagas disease)". Infect Dis Clin North Am. 26 (2): 275–91. doi:10.1016/j.idc.2012.03.002. PMID 22632639.
- ↑ 2.0 2.1 Tarleton RL, Reithinger R, Urbina JA, Kitron U, Gürtler RE (2007). "The challenges of Chagas Disease-- grim outlook or glimmer of hope". PLoS Med. 4 (12): e332. doi:10.1371/journal.pmed.0040332. PMC 2222930. PMID 18162039.
- ↑ Bern C, Martin DL, Gilman RH (2011). "Acute and congenital Chagas disease". Adv Parasitol. 75: 19–47. doi:10.1016/B978-0-12-385863-4.00002-2. PMID 21820550.
- ↑ 4.0 4.1 Schijman AG, Bisio M, Orellana L, Sued M, Duffy T, Mejia Jaramillo AM; et al. (2011). "International study to evaluate PCR methods for detection of Trypanosoma cruzi DNA in blood samples from Chagas disease patients". PLoS Negl Trop Dis. 5 (1): e931. doi:10.1371/journal.pntd.0000931. PMC 3019106. PMID 21264349.
- ↑ Duffy T, Bisio M, Altcheh J, Burgos JM, Diez M, Levin MJ; et al. (2009). "Accurate real-time PCR strategy for monitoring bloodstream parasitic loads in chagas disease patients". PLoS Negl Trop Dis. 3 (4): e419. doi:10.1371/journal.pntd.0000419. PMC 2667272. PMID 19381287.
- ↑ 6.0 6.1 6.2 6.3 "Public Health Image Library (PHIL)".