What Are The Different Diagnostic Tests For SARS?
Chest x-ray, blood cultures and tests to detect viral pathogens are helpful in diagnosing SARS.
Tests to diagnose SARS include:
- Chest X-Ray (CXR) or chest CT scan- In most people with SARS, changes on CXR or chest CT show pneumonia.
- Enzyme-linked immunosorbent assay (ELISA) test- This test detects antibodies to SARS reliably, but only 21 days after the onset of symptoms.
- Immunofluorescence assay- This test can detect antibodies 10 days after the onset of the disease.
- Reverse transcription polymerase chain reaction (RT-PCR) test- SARS-CoV can be detected in clinical specimens such as blood, stool and nasal secretions with the help of this test.
- Antibody tests for SARS- Serologic testing also can be performed to detect SARS-CoV antibodies produced after infection.
- Viral culture and direct isolation of the SARS virus- For a viral culture, a small sample of tissue or fluid that may be infected is placed in a container along with cells in which the virus can grow. If the virus grows in the culture, it will cause changes in the cells that can be seen under a microscope.
- Serologic testing- A serologic test is a laboratory method for detecting the presence and/or level of antibodies to an infectious agent in serum from a person.
Blood clotting tests
- Complete blood count (CBC) - White blood cell (neutrophils and lymphocytes) and platelet counts are often low.
All current tests have some limitations. They may not be able to easily identify a SARS case during the first week of the illness, when it is most important.