Legionellosis laboratory findings: Difference between revisions
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__NOTOC__ | __NOTOC__ | ||
{{Legionellosis}} | {{Legionellosis}} | ||
{{CMG}} | {{CMG}} | ||
==Laboratory Findings== | ==Laboratory Findings== | ||
* [[Complete blood count]] and differential count - [[ | * [[Complete blood count]] and differential count - [[lymphopenia]] and rarely [[pancytopenia]] | ||
* Serum electrolytes - [[hyponatremia]] | * Serum electrolytes - [[hyponatremia]] | ||
* [[Liver function test]]s - elevated [[bilirubin]] levels | * [[Liver function test]]s - elevated [[bilirubin]] levels | ||
* [[Urinalysis]] - [[proteinuria]] | * [[Urinalysis]] - [[proteinuria]] | ||
* | * [[Sputum]] Gram staining - Gram negative rods | ||
==Diagnostic Studies== | |||
* [[Urine]] [[antigen]] test - the urine antigen test is simple, quick, and very reliable; however it will only detect ''[[Legionella pneumophila]]'' serogroup #1. If the patient has [[pneumonia]] and the test is positive then the patient is considered to have Legionnaires’ disease. Also the urine antigen test will not identify the specific subtyping so it cannot be used to match the patient with the environmental source of infection. (sensitivity 70%, specificity 100%) | |||
* Cultures - Expectorated sputum, endotracheal aspirates, pleural fluid, blood, or tissue samples may be sent for culture. Unlike serology and urine antigen testing, the yield of cultures is independent of serotype and may be positive in cases of non-''Legionella pneumophila'' species. (sensitivity 80%, specificity 100%) | |||
* [[Antibody]] test (paired sera) - compare [[antibody]] levels to ''[[Legionella]]'' in two blood samples obtained 3 to 6 weeks apart. A 4-fold or greater rise in titer between acute and convalescent sera is diagnostic. (sensitivity 70-80%, specificity > 90%) | |||
* Immunofluorescent microscopy with direct fluorescent antibody - detects Legionella in respiratory tract tissues or fluids (sensitivity 25-75%, specificity 95%) | |||
* [[Polymerase chain reaction|Polymerase chain reaction (PCR)]] - detects Legionella DNA in sputum, pleural fluid, [[bronchoalveolar lavage]] samples, pulmonary tissues, urine, or environmental water. | |||
==References== | ==References== | ||
{{reflist|2}} | {{reflist|2}} | ||
[[Category:Infectious disease]] | [[Category:Infectious disease]] | ||
[[Category:Pulmonology]] | [[Category:Pulmonology]] | ||
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[[Category:Medical disasters]] | [[Category:Medical disasters]] | ||
[[Category:Needs overview]] | [[Category:Needs overview]] | ||
Revision as of 12:40, 31 July 2015
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Legionellosis Microchapters |
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Legionellosis laboratory findings On the Web |
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American Roentgen Ray Society Images of Legionellosis laboratory findings |
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Risk calculators and risk factors for Legionellosis laboratory findings |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Laboratory Findings
- Complete blood count and differential count - lymphopenia and rarely pancytopenia
- Serum electrolytes - hyponatremia
- Liver function tests - elevated bilirubin levels
- Urinalysis - proteinuria
- Sputum Gram staining - Gram negative rods
Diagnostic Studies
- Urine antigen test - the urine antigen test is simple, quick, and very reliable; however it will only detect Legionella pneumophila serogroup #1. If the patient has pneumonia and the test is positive then the patient is considered to have Legionnaires’ disease. Also the urine antigen test will not identify the specific subtyping so it cannot be used to match the patient with the environmental source of infection. (sensitivity 70%, specificity 100%)
- Cultures - Expectorated sputum, endotracheal aspirates, pleural fluid, blood, or tissue samples may be sent for culture. Unlike serology and urine antigen testing, the yield of cultures is independent of serotype and may be positive in cases of non-Legionella pneumophila species. (sensitivity 80%, specificity 100%)
- Antibody test (paired sera) - compare antibody levels to Legionella in two blood samples obtained 3 to 6 weeks apart. A 4-fold or greater rise in titer between acute and convalescent sera is diagnostic. (sensitivity 70-80%, specificity > 90%)
- Immunofluorescent microscopy with direct fluorescent antibody - detects Legionella in respiratory tract tissues or fluids (sensitivity 25-75%, specificity 95%)
- Polymerase chain reaction (PCR) - detects Legionella DNA in sputum, pleural fluid, bronchoalveolar lavage samples, pulmonary tissues, urine, or environmental water.