Q fever laboratory tests
|
Q fever Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Q fever laboratory tests On the Web |
|
American Roentgen Ray Society Images of Q fever laboratory tests |
|
Risk calculators and risk factors for Q fever laboratory tests |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Ahmed Younes M.B.B.CH [2]
Lab tests:
Serologic testing for Q fever:
- Indirect immunofluorescence (IIF) is the method of choice for antibody detection and is preferred over ELISA and complement fixation.
- Antibodies starts to be detected after 7-14 days of infection with most patients testing positive by the third week.
- Anti phase II antibodies are tested first. If positive, anti phase I antibodies are tested.
- After acute infection, serologic follow up for serum anti phase I IgG antibodies. The test is done twice every 3 months for 2 years. If it's positive, Transesophageal echo should be done to rule out endocarditis.
- All serologic test results should be used in the context of clinical data because false positive test results are seen in many other diseases (e.g. leptospirosis).
Polymerase chain reaction (PCR):
- PCR can be used to detect C. brutenii DNA in cultures and clinical samples.
- PCR is positive in the first week of infection, thus it can be used to diagnose Q fever in patients who are serologically negative in the early stages of the disease.
- Quantitative PCR also can be used in patients whom anti phase II IgG antibodies are persistently positive to detect chronic Q fever.
Cultures:
- C. brutenii doesn’t grow on ordinary blood cultures but can be cultivated on special media as embryonated eggs or cell culture.
- C. brutenii is extremely infectious and samples should be handled with caution.
Liver function tests:
- 2-3 fold increase in AST and ALT is seen in most of the patients.