KUALA LUMPUR--Malaysian authorities have begun using COVID-19 antibody rapid test kits to supplement laboratory tests as the number of cases in the country grows, a senior health official said on Tuesday.

Officials in Malaysia, as elsewhere, had initially rejected the use of the serology test kits, which can show the presence of antibodies in people who have been infected.

Like other countries, it instead chose polymerase chain reaction, or PCR, laboratory tests, which detect the presence of the novel coronavirus itself and are seen as more reliable.

But as the number of suspected cases needing testing has risen, the turnaround time for laboratory test results had increased from around 6 hours to as many as two days or more, Director-General of Health Noor Hisham Abdullah told reporters.

Malaysia reported 170 new coronavirus cases on Tuesday, taking the total to nearly 5,000 infections, the second highest in Southeast Asia, with 82 deaths. It had done nearly 82,000 PCR tests as of Monday and reported over 8,000 pending lab results earlier this month, before it stopped publishing backlog data.

To reduce the testing backlog, the close contacts of people infected will now receive the antibody tests at the end of their 14-day mandatory quarantine period.

“On the 13th day, we will use the antibody or serology tests ... and if it comes back positive, then we will carry out the PCR test again,” Noor Hisham said.

“But if the antibody test comes back negative, then you’re in the clear. This is how we are trying to reduce the number of PCR lab tests.”

A person who tested negative can then be discharged from quarantine, freeing up state resources used to monitor them, but they would still be required to self-isolate under movement curbs imposed by the government until April 28 to limit the virus’ spread.

Countries hope antibody tests may one day help them to ease movement curbs by identifying people who may have acquired immunity, but it is not yet clear if that is possible.

Some doctors had been calling for Malaysia to use new rapid test kits--both antibody and antigen--to widen testing and reduce the backlog of cases, but like other countries, it has been awaiting trial results.

A shortage of laboratory testing supplies and difficulty in procuring them have made it hard to ramp up capacity.

Malaysia last week warned of a shortage of reagents, a chemical used in diagnostic tests to detect the presence of the coronavirus.

Noor Hisham on Tuesday also warned that the country was running low on personal protective equipment (PPEs) for health workers, with supplies of some items expected to last just another 19 days.