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Old tests fail to detect hepatitis

Health officials reported yesterday that commonly used blood tests are insufficient for detecting the hepatitis B virus, stating that a substantial percentage of cases go undetected.

Lin Mung-chiao (林盟喬), senior technical specialist at the Kaohsiung City Government Health Department, reported recent findings that traditional blood tests used to detect hepatitis B failed to identify 30 percent of virus carriers on first trial and 13 percent on second trial.

Lin explained that around 12 percent to 18 percent of Kaohsiung residents over the age of 16, many of whom have never received the Hepatitis B vaccine, are virus carriers. Furthermore, the vaccine is ineffective in carriers, leading to a high incidence rate of liver cancer.

He said that around 440 residents of Kaohsiung die of liver cancer each year.

"In most cases, initial tests seek to confirm the existence of antibodies. If antibodies already exist, then the patient does not have the hepatitis B virus. However, if the test turns out negative, then another test is administered to confirm the existence of antigens," Lin said.

"The study shows that traditional blood tests failed to confirm the existence of antigens in several students," he said.

Although the research focused primarily on Kaohsiung residents, Lin said that the situation was probably the same in the rest of the country.

According to Lin, the research was conducted using two different testing methods.

Four hundred youths between the ages of 15 and 20 were given the blood test traditionally used in detecting hepatitis B, known in the medical field as Enzyme-Linked Immunosorbent Assay (ELISA). A different test, the Polymerase Chain Reaction (PCR) test, was also administered on the sample group.

The study proved that the PCR test found several cases of hepatitis B viral infection that went undetected by the ELISA test.

However, Lin was cautious in ruling out the ELISA test.

"I don't think that this necessarily means that the ELISA test is completely incorrect. I would urge people to have the test performed multiple times and to utilize both tests." Lin said.

However, he admitted that the PCR test could cost as much as NT$5,000.

Lin further noted that while several of the youths tested were infected, none exhibited any physical symptoms.

"Symptoms are more noticeable in adults. The youths tested were never vaccinated but seemed to be in general good health," he said.

He warned that the virus could become a chronic problem that would plague one's entire life if left untreated.

The study further indicated that a high percentage of the students who initially registered a lack of natural Hepatitis B antibodies later exhibited the antibodies in subsequent tests.

Lin said that over 20 percent of the unvaccinated students eventually developed natural antibodies, a process referred to as serum conversion.

"Before the age of 25, there is the chance that hepatitis B antibodies can be developed, allowing one's body protection against the hepatitis B virus. After the age of 25 however, serum conversion is quite unlikely and vaccinations are needed to stop the virus," Lin said.
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