Smallpox laboratory tests: Difference between revisions
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==Overview== | ==Overview== | ||
The [[polymerase chain reaction]] test and the growth of the [[virus]] in specific [[cell culture]]s allow the identification of the [[smallpox virus]]. | |||
==Laboratory Findings== | ==Laboratory Findings== | ||
There are laboratory tests to specifically identify the [[smallpox virus]]. However, in a patient with low to medium level of suspicion of smallpox, a [[false-positive]] result would have | There are laboratory tests to specifically identify the [[smallpox virus]]. However, in a patient with low to medium level of suspicion of [[smallpox]], a [[false-positive]] result would have great personal and social impacts. Therefore, these tests must be used cautiously, and according to certain guidelines.<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref><ref name="pmid15546084">{{cite journal| author=Seward JF, Galil K, Damon I, Norton SA, Rotz L, Schmid S et al.| title=Development and experience with an algorithm to evaluate suspected smallpox cases in the United States, 2002-2004. | journal=Clin Infect Dis | year= 2004 | volume= 39 | issue= 10 | pages= 1477-83 | pmid=15546084 | doi=10.1086/425500 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15546084 }} </ref><ref name="pmid14625530">{{cite journal| author=Besser JM, Crouch NA, Sullivan M| title=Laboratory diagnosis to differentiate smallpox, vaccinia, and other vesicular/pustular illnesses. | journal=J Lab Clin Med | year= 2003 | volume= 142 | issue= 4 | pages= 246-51 | pmid=14625530 | doi=10.1016/S0022-2143(03)00146-X | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=14625530 }} </ref><ref name="Madeley2003">{{cite journal|last1=Madeley|first1=CR|title=Diagnosing smallpox in possible bioterrorist attack|journal=The Lancet|volume=361|issue=9352|year=2003|pages=97–98|issn=01406736|doi=10.1016/S0140-6736(03)12241-6}}</ref> | ||
===Laboratory Criteria for Confirmation=== | ===Laboratory Criteria for Confirmation=== | ||
For laboratory testing, the following specimens may be requested: | For laboratory testing, the following [[Laboratory specimen|specimens]] may be requested: | ||
* Lesion specimens | * Lesion [[Laboratory specimen|specimens]] | ||
* Blood | * [[Blood]] | ||
* Tonsilar swabs | * [[Tonsils|Tonsilar]] swabs | ||
* Biopsy | * [[Biopsy]] | ||
For patients defined as high risk for smallpox, the following tests are available:<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref> | For patients defined as high risk for [[smallpox]], the following tests are available:<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref> | ||
====Polymerase Chain Reaction (PCR)==== | ====Polymerase Chain Reaction (PCR)==== | ||
* Identifies [[smallpox virus]] [[DNA]] in the clinical specimen | * Identifies [[smallpox virus]] [[DNA]] in the clinical [[Laboratory specimen|specimen]] | ||
====Electron Microscopy==== | ====Electron Microscopy==== | ||
* Identifies typical | * Identifies typical [[virions]] with brick shape | ||
* Can not distinguish [[smallpox virus]] [[DNA]] from other [[orthopoxvirus]]es | * Can not distinguish [[smallpox virus]] [[DNA]] from other [[orthopoxvirus]]es | ||
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====Cell Culture==== | ====Cell Culture==== | ||
* [[Smallpox virus]] may be grown in different [[cell]] lines, producing characteristic pocks on some [[cells]] of chicken embryos, enabling species identification | * [[Smallpox virus]] may be grown in different [[cell]] lines, producing characteristic pocks on some [[cells]] of chicken embryos, enabling [[species]] identification | ||
''Laboratory diagnostic testing for smallpox virus should be conducted in a CDC Laboratory Response Network (LRN) laboratory utilizing LRN-approved PCR tests and protocols for | ''Laboratory diagnostic testing for [[smallpox virus]] should be conducted in a CDC Laboratory Response Network (LRN) laboratory utilizing LRN-approved PCR tests and protocols for this virus. Initial confirmation of a smallpox outbreak requires additional testing by the CDC.'' | ||
''Note: Generic orthopox PCR and negative stain electron microscopy (EM) identification of a pox virus in a clinical specimen are suggestive of an'''orthopox ''' virus infection but not diagnostic for smallpox.'' | ''Note: Generic orthopox in PCR and negative stain electron microscopy (EM) identification of a pox virus in a clinical specimen, are suggestive of an'''orthopox ''' virus infection, but not diagnostic for smallpox.'' | ||
===Laboratory Test Algorithm=== | ===Laboratory Test Algorithm=== | ||
The algorithm below describes the laboratory protocol for a patient who presents with a generalized [[vesicular]] or [[pustule|pustular]] [[rash]]. This algorithm is based on the risk level of the patient to be [[infected]] with [[smallpox]] virus.<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref> | |||
[[Image:Smallpox lab test.jpg|thumb|center|800px|<SMALL><SMALL>''[http://emergency.cdc.gov/agent/smallpox/diagnosis/pdf/poxalgorithm5-2-14.pdf Adapted from Laboratory Response Network (LRN [CDC]), Laboratory Response Network.]''<ref name="LRN(CDC)">{{Cite web | title = Public Health Image Library (PHIL), Centers for Disease Control and Prevention | url = http://emergency.cdc.gov/agent/smallpox/diagnosis/pdf/poxalgorithm5-2-14.pdf}}</ref></SMALL></SMALL>]] | |||
==References== | ==References== | ||
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[[Category:Needs overview]] | [[Category:Needs overview]] | ||
[[Category:Disease]] | [[Category:Disease]] | ||
[[Category:Pediatrics]] | [[Category:Pediatrics]] | ||
[[Category:Smallpox]] | [[Category:Smallpox]] | ||
Latest revision as of 19:04, 18 September 2017
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Smallpox laboratory tests On the Web |
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American Roentgen Ray Society Images of Smallpox laboratory tests |
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Risk calculators and risk factors for Smallpox laboratory tests |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
The polymerase chain reaction test and the growth of the virus in specific cell cultures allow the identification of the smallpox virus.
Laboratory Findings
There are laboratory tests to specifically identify the smallpox virus. However, in a patient with low to medium level of suspicion of smallpox, a false-positive result would have great personal and social impacts. Therefore, these tests must be used cautiously, and according to certain guidelines.[1][2][3][4]
Laboratory Criteria for Confirmation
For laboratory testing, the following specimens may be requested:
For patients defined as high risk for smallpox, the following tests are available:[1]
Polymerase Chain Reaction (PCR)
- Identifies smallpox virus DNA in the clinical specimen
Electron Microscopy
- Identifies typical virions with brick shape
- Can not distinguish smallpox virus DNA from other orthopoxviruses
Serologic Tests
- Not able to distinguish smallpox virus from other orthopoxviruses
Cell Culture
- Smallpox virus may be grown in different cell lines, producing characteristic pocks on some cells of chicken embryos, enabling species identification
Laboratory diagnostic testing for smallpox virus should be conducted in a CDC Laboratory Response Network (LRN) laboratory utilizing LRN-approved PCR tests and protocols for this virus. Initial confirmation of a smallpox outbreak requires additional testing by the CDC.
Note: Generic orthopox in PCR and negative stain electron microscopy (EM) identification of a pox virus in a clinical specimen, are suggestive of anorthopox virus infection, but not diagnostic for smallpox.
Laboratory Test Algorithm
The algorithm below describes the laboratory protocol for a patient who presents with a generalized vesicular or pustular rash. This algorithm is based on the risk level of the patient to be infected with smallpox virus.[1]
References
- ↑ 1.0 1.1 1.2 Moore, Zack S; Seward, Jane F; Lane, J Michael (2006). "Smallpox". The Lancet. 367 (9508): 425–435. doi:10.1016/S0140-6736(06)68143-9. ISSN 0140-6736.
- ↑ Seward JF, Galil K, Damon I, Norton SA, Rotz L, Schmid S; et al. (2004). "Development and experience with an algorithm to evaluate suspected smallpox cases in the United States, 2002-2004". Clin Infect Dis. 39 (10): 1477–83. doi:10.1086/425500. PMID 15546084.
- ↑ Besser JM, Crouch NA, Sullivan M (2003). "Laboratory diagnosis to differentiate smallpox, vaccinia, and other vesicular/pustular illnesses". J Lab Clin Med. 142 (4): 246–51. doi:10.1016/S0022-2143(03)00146-X. PMID 14625530.
- ↑ Madeley, CR (2003). "Diagnosing smallpox in possible bioterrorist attack". The Lancet. 361 (9352): 97–98. doi:10.1016/S0140-6736(03)12241-6. ISSN 0140-6736.
- ↑ "Public Health Image Library (PHIL), Centers for Disease Control and Prevention" (PDF).