Rapid test does not diagnose H5N1

Previously, rapid test results used to diagnose H5N1 were identified as unreliable. However, some provinces continue to use. Deputy Minister of Health Trinh Quan Huan said: "No rapid test is recommended for use in H5N1 diagnosis" .

Mr. Huan said, the World Health Organization (WHO) has not recommended the use of rapid test tools to identify patients infected with H5N1 virus. The Ministry of Health has no plan to apply this measure to provinces. Only authorized medical units have the right to perform tests of samples suspected of being infected with H5N1 using modern techniques. And the South only has the Pasteur Institute to conclude whether a case is infected with H5N1.

Implementation of viral RNA extract at the Pasteur Institute in Ho Chi Minh City.(Photo: My Lan / VNE)

According to Huan, provinces can only rely on the epidemic situation that is happening and related symptoms that initially isolate suspected H5N1 cases. After that, take samples of specimens and send them to the units with the function of testing (20 provinces in the South do not have any H5N1 diagnostic laboratory). All samples are sent to the Hospital for Tropical Diseases (HCMC) or Pasteur Institute for testing. The conclusion of Pasteur Institute is the final result.

According to Dr. Nguyen Thanh Long, Head of Respiratory Virus Department Pasteur Institute, before that Pasteur Institute and Tropical Diseases Hospital sponsored by some rapid test kits to diagnose H5N1 but gave inconsistent results, no reliable so only after a while, both units are not used anymore.

If now, where else to use rapid test to diagnose H5N1, this will not bring any results. Because rapid tests cannot confirm H5N1 infection but only initial screening but reliability "can be said to be completely absent ," Dr. Long admitted. According to him, in order to conclude whether a case is infected with H5N1, the specimen should be tested with RT-PCR or Realtime RT-PCR techniques.

When suspected of being infected with H5N1, the provinces took specimens to the Pasteur Institute. Here, the testing process involves a cycle: extracting the viral RNA to give it to a thermostat - to run the electrophoresis - to produce results.

With RT-PCR, it is theoretically possible to get accurate results from 98 to 99%. This technique was first used in the diagnosis of H5N1. If a positive result can be confirmed immediately. But if the RT-PCR technique produces a negative result, but there are typical clinical symptoms, the Realtime RT-PCR test can be followed to make a final conclusion. According to experts, the theoretical accuracy of Realtime RT-PCR method is 100%. "Although more accurate, this technique is only used when absolutely necessary because the cost is much higher than RT-PCR testing technique," Dr. Long explained.

In theory, an H5N1 test only takes 6 hours to produce results. But due to the lack of machinery, the Institute has to wait almost every day for all the specimens received in the day to test, this is why 24 hours to have results. Mr. Long also said that from the beginning of 2006 until now, only 9 specimens suspected of being infected with H5N1 from sending places, greatly reduced compared to before.

Huan added that in 2006, the Ministry of Health plans to establish a number of rooms at the provincial level that can test H5N1 by RT-PCR.

My Lan