SINGAPORE - Those with type O blood, your help is needed.

The Singapore Red Cross and Health Sciences Authority are calling on donors with type O blood to come forward over the next two weeks, amid a low national stock level for the blood group.

About 500 donors are required to bring the type O blood stock up to a healthy level, the agencies said in a statement on Friday (Sept 28).

As of Friday, there was about only half of the required stockpile, the statement added.

The agencies said that they aim to have at least six days' supply of type O blood to meet daily transfusion needs and bleeding emergencies in Singapore.

Donors are encouraged to visit Bloodbank @ HSA, Bloodbank @ Dhoby Ghaut, Bloodbank @ Woodlands and Bloodbank @ Westgate Tower as soon as they can.

As a universal blood group, type O blood is required for all patients during emergency situations when their blood groups are not known.

Related Story Questions you may have about blood... answered

Related Story Keeping donor blood flowing in Singapore amid seasonal dip

In response to queries from The Straits Times, a HSA spokesman said that the daily national blood stock and blood usage are monitored closely by HSA and the Singapore Red Cross, and strategies are in place to recall donors whenever there is a dip.

The usage of type O blood is the highest among all blood types, as it is a universal blood group and nearly half of the patients belong to this group, the spokesman added.

Therefore, slight changes to the usage and collection can affect the overall blood stock.

While the Singapore Red Cross has been making efforts to mobilise donors, public response has been slow, said the spokesman.

Efforts include working with organisers of mobile blood donation centres to urge the public to come forward, appealing for donors via social media, as well as issuing SMSes to recall blood donors, particularly those who are due for their next blood donation.

Healthy individuals with type O blood who are between 16 and 60 years old are encouraged to donate blood. They have to weigh at least 45kg.

Donors who have not made a donation in the past 12 weeks are also encouraged to come forward.

To donate blood, Singaporeans are required to take along their NRIC, while non-Singaporeans should go with their passport.

A signed parental consent form is required for 16- or 17-year-old donors.

The form can be found at www.hsa.gov.sg/parent_consent

Before a donation, donors are advised to eat a light meal and drink plenty of fluids.

They should also ensure that they have adequate rest the night before the donation and on the day itself.

For more information, or to make an appointment, visit www.hsa.gov.sg/donor_criteria or call 6220-0183.

Information on upcoming community blood drives can be found at www.redcross.sg/donateblood

Community and corporate groups who wish to organise group donations at the blood banks can call the Singapore Red Cross on 6220-0183 for more details.