Ehrlichiosis laboratory findings: Difference between revisions
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==Overview== | ==Overview== | ||
There are three primary laboratory methods to diagnose an ehrlichiosis infection, polymerase chain reaction (PCR), peripheral blood smear, and an immunofluorescence assay (IFA). Polymerase chain reaction and peripheral blood smear exams are most effective when conducted early on in the diagnoses. The gold standard serologic test for ehrlichiosis is the immunofluorescence assay. The test is most effective when conducted once early on in the infection and a second time, later in the infection. Infection rates will show in increase within an IFA as the illness progresses. <ref name= "CDC sym"> Centers for Disease Control and Prevention. Ehrlichiosis symptoms. http://www.cdc.gov/ehrlichiosis/symptoms/Accessed January 20,2016.</ref> | There are three primary laboratory methods to diagnose an ehrlichiosis infection, [[polymerase chain reaction]] (PCR), [[peripheral blood smear]], and an [[Immunofluorescence assay|immunofluorescence]] assay (IFA). Polymerase chain reaction and peripheral blood smear exams are most effective when conducted early on in the diagnoses. The gold standard serologic test for ehrlichiosis is the immunofluorescence assay. The test is most effective when conducted once early on in the infection and a second time, later in the infection. Infection rates will show in increase within an IFA as the illness progresses. <ref name="CDC sym">Centers for Disease Control and Prevention. Ehrlichiosis symptoms. http://www.cdc.gov/ehrlichiosis/symptoms/Accessed January 20,2016.</ref> | ||
==Laboratory Findings== | ==Laboratory Findings== | ||
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===Polymerase chain reaction (PCR)=== | ===Polymerase chain reaction (PCR)=== | ||
*Most effective within the acute phase of illness (first week of illness). | *Most effective within the acute phase of illness (first week of illness). | ||
*Negative result does not completely rule out analysis. <ref name= "CDC sym"> Centers for Disease Control and Prevention. Ehrlichiosis symptoms. http://www.cdc.gov/ehrlichiosis/symptoms/Accessed January 20,2016.</ref> | *Negative result does not completely rule out analysis. <ref name="CDC sym">Centers for Disease Control and Prevention. Ehrlichiosis symptoms. http://www.cdc.gov/ehrlichiosis/symptoms/Accessed January 20,2016.</ref> | ||
===Peripheral Blood Smear=== | ===Peripheral Blood Smear=== | ||
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**E. chaffeensis infects monocytes. | **E. chaffeensis infects monocytes. | ||
**E. ewingii infects granulocytes. | **E. ewingii infects granulocytes. | ||
*Verification of infecting species must be confirmed with a culture isolation at a specialized laboratory. <ref name= "CDC sym"> Centers for Disease Control and Prevention. Ehrlichiosis symptoms. http://www.cdc.gov/ehrlichiosis/symptoms/Accessed January 20,2016.</ref> | *Verification of infecting species must be confirmed with a culture isolation at a specialized laboratory. <ref name="CDC sym">Centers for Disease Control and Prevention. Ehrlichiosis symptoms. http://www.cdc.gov/ehrlichiosis/symptoms/Accessed January 20,2016.</ref> | ||
===Immunofluorescence assay=== | ===Immunofluorescence assay=== | ||
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*A second sample should be taken 2-4 weeks later. | *A second sample should be taken 2-4 weeks later. | ||
*Typically the first count is low, however will significantly increase by the second sample. | *Typically the first count is low, however will significantly increase by the second sample. | ||
*Testing should include both an IgM and IgG titer. <ref name= "CDC sym"> Centers for Disease Control and Prevention. Ehrlichiosis symptoms. http://www.cdc.gov/ehrlichiosis/symptoms/Accessed January 20,2016.</ref> | *Testing should include both an IgM and IgG titer. <ref name="CDC sym">Centers for Disease Control and Prevention. Ehrlichiosis symptoms. http://www.cdc.gov/ehrlichiosis/symptoms/Accessed January 20,2016.</ref> | ||
==References== | ==References== | ||
Revision as of 16:48, 22 January 2016
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Ilan Dock, B.S.
Overview
There are three primary laboratory methods to diagnose an ehrlichiosis infection, polymerase chain reaction (PCR), peripheral blood smear, and an immunofluorescence assay (IFA). Polymerase chain reaction and peripheral blood smear exams are most effective when conducted early on in the diagnoses. The gold standard serologic test for ehrlichiosis is the immunofluorescence assay. The test is most effective when conducted once early on in the infection and a second time, later in the infection. Infection rates will show in increase within an IFA as the illness progresses. [1]
Laboratory Findings
Polymerase chain reaction (PCR)
- Most effective within the acute phase of illness (first week of illness).
- Negative result does not completely rule out analysis. [1]
Peripheral Blood Smear
- Most effective during the first week of illness.
- May reveal morulae (microcolonies of ehrlichiae.)
- Identifying the type of infected blood cell may indicate the infecting species.
- E. chaffeensis infects monocytes.
- E. ewingii infects granulocytes.
- Verification of infecting species must be confirmed with a culture isolation at a specialized laboratory. [1]
Immunofluorescence assay
- Gold standard serologic test for ehrlichiosis.
- Sample should be extracted as early in the disease as possible.
- A second sample should be taken 2-4 weeks later.
- Typically the first count is low, however will significantly increase by the second sample.
- Testing should include both an IgM and IgG titer. [1]
References
- ↑ 1.0 1.1 1.2 1.3 Centers for Disease Control and Prevention. Ehrlichiosis symptoms. http://www.cdc.gov/ehrlichiosis/symptoms/Accessed January 20,2016.