A diagnostic kit is a key tool that helps doctors to quickly identify patients infected with a viral infection. But with the SARS epidemic, doctors so far do not have that luxury. Because the current attack is the first known attack of the SARS virus on humans and so no one has bothered to develop a kit to diagnose it quickly.
So doctors are having a tough time to identify the patients with SARS infection those with the more common pneumonia disease or people with respiratory problems.
Doctors now rely on chest X-rays and a list of symptoms: fever, dry cough, malaise and lots of luck to pick out the SARS cases. "We need a test now," insists Dr Klaus Stöhr, who directs the scientific investigation of SARS for the World Health Organization. "We had hoped to have one by now, but it is going to take longer than we thought."
There are two ways to make a diagnostic kit. There can be an appropriate kit than detect the virus itself. The other option is to detect the presence of antibodies, which are essentially proteins produced by the immune system to counter the virus.
The CDC has developed two preliminary kits which substantially in the detection of the SARS virus. A standard test, called polymerase chain reaction (PCR) has been used to successfully identify the SARS virus in patients. It is not a full proof yet it has been successful because it has not given any false reports. However, it couldn't identify the virus in some specimens.
By using the well known ELISA test which uses antibodies as the measuring mechanism, researchers have been able to detect the SARS virus. This test is more effective around 20 days of infection and unless it is extended to work in the early stages of the infection, it may not be very useful. There are several other problems in developing a diagnostic kit quickly. Its increasing presence in various humans has added to the problem. The antibody's presence was different in different human bodies. While it was believed to be present mostly in the mouth or saliva, now it is found in the blood too. And after the fifth day, the virus moves to the respiratory track which reduces the possibility of detection.
