SINGAPORE - All patients with pneumonia in public hospitals have been undergoing tests for the coronavirus since last week, said the Ministry of Health (MOH) on Tuesday (Feb 4).

It said this on the same day it announced the confirmation of six new cases of the virus here.

One of the cases, a 28-year-old female Singapore permanent resident, had gone to Tan Tock Seng Hospital's emergency department on Jan 30 and was discharged as her chest X-ray did not indicate she had pneumonia.

On Monday, however, she went to Singapore General Hospital and was diagnosed with pneumonia.

Despite having no recent travel history to China, she was classified as a suspect case and immediately isolated, before being confirmed with the coronavirus later that night.

MOH's director of medical services, Associate Professor Kenneth Mak, said on Tuesday that the woman had been tested for the virus as a result of the ministry's earlier decision to screen all pneumonia patients for it.

Pneumonia was the second-largest cause of death in Singapore in 2018, accounting for over one in five deaths here.

There are about 500 to 600 patients with pneumonia here each week who will need to be tested for the virus.

Prof Mak said that Singapore is able to handle the demand for tests.

"We don't think the testing capacity is going to be an issue. We in fact have sufficient capacity to test these individuals (and) those who come on as suspected cases further downstream as well," he said.

A polymerase chain reaction (PCR) test is used to screen individuals for the virus here, said Prof Mak.

This is a test which analyses a short sequence of a person's DNA by copying it multiple times.

PCR tests are used for a number of reasons, including the detection of bacteria or viruses, diagnosing genetic disorders and DNA fingerprinting.

Prof Mak said such tests typically take between two and four hours, but additional time is often needed to verify the results, sometimes extending the entire process to 24 hours.

On Singapore's efforts to test all pneumonia patients, he added: "It's an ongoing process... As new cases come in, they will also be tested in turn."

The Straits Times understands that, in addition to efforts by the public hospitals, the four private hospitals under Parkway Pantai will also be testing pneumonia patients for the virus.

Additional reporting by Joyce Teo