Previously, rapid test results for diagnosing H5N1 were deemed unreliable. However, some provinces continue to use them. Deputy Minister of Health Trịnh Quân Huấn affirmed: “No rapid tests are recommended for diagnosing H5N1.”
Mr. Huấn stated that the World Health Organization (WHO) has not recommended the use of rapid test kits to identify individuals infected with the H5N1 virus. The Ministry of Health also does not plan to implement this method across provinces. Only designated health units are authorized to conduct tests on suspected H5N1 samples using modern techniques. In the southern region, only the Pasteur Institute has the authority to conclude whether a case is infected with H5N1.
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Extracting viral RNA at the Pasteur Institute in Ho Chi Minh City. (Photo: Mỹ Lan/VNE) |
According to Mr. Huấn, provinces can only rely on the ongoing epidemiological situation and related symptoms to initially isolate suspected H5N1 cases. Samples are then sent to specialized units for testing (as of now, no provinces in the southern region have laboratories specifically for diagnosing H5N1). All samples are forwarded to the Tropical Diseases Hospital (Ho Chi Minh City) or the Pasteur Institute for examination. The conclusion from the Pasteur Institute is considered the definitive result.
Dr. Nguyễn Thanh Long, Head of the Respiratory Virus Department at the Pasteur Institute, noted that previously both the Pasteur Institute and the Tropical Diseases Hospital were funded by WHO for some rapid test kits to diagnose H5N1. However, due to inconsistent and unreliable results, neither institution uses them anymore.
If any locations are still using rapid tests to diagnose H5N1, such measures are unlikely to yield any results. This is because rapid tests cannot confirm H5N1 infection; they only serve as initial screening tools, and the reliability is “completely nonexistent.” Dr. Long explained. Furthermore, to conclusively determine whether a case is infected with H5N1, the sample must undergo testing using RT-PCR or Realtime RT-PCR techniques.
When H5N1 infection is suspected, provinces collect samples and send them to the Pasteur Institute. The testing process involves a cycle: extracting the viral RNA to place into a thermocycler, conducting electrophoresis, and producing results.
Using RT-PCR, theoretically, results can be accurate from 98 to 99%. This technique is primarily used for diagnosing H5N1. If a positive result is obtained, it can be confirmed immediately. However, if RT-PCR yields a negative result but the patient presents typical clinical symptoms, a further examination using Realtime RT-PCR is required to reach a final conclusion. Experts assess that the theoretical accuracy of the Realtime RT-PCR method is 100%. “Although more accurate, this technique is only used when absolutely necessary due to its significantly higher costs compared to RT-PCR testing,” Dr. Long explained.
Theoretically, an H5N1 test can yield results in just 6 hours. However, due to a lack of equipment, the Institute must wait until the end of the day to process all samples received, which is why results take about 24 hours. Mr. Long also mentioned that since the beginning of 2006, only 9 samples suspected of H5N1 infection have been sent from various locations, a significant decrease from previous years.
Mr. Huấn added that in 2006, the Ministry of Health plans to establish several provincial laboratories capable of conducting H5N1 tests using RT-PCR techniques.
Mỹ Lan
