Under fluorescent lights and amid the steady humming of machines in the background, large insulated cooler boxes - similar to those typically used to store cold drinks - are wheeled in on pushcarts.
One by one, the lids of the boxes are unfastened, revealing transparent packets filled with an opaque, carmine liquid. People donning papery lab scrubs sift through these palm-size blood bags and arrange them neatly on a plain grey bench.
Work has begun at the Health Sciences Authority's (HSA) blood processing laboratory, a spacious set-up behind the walls of the blood bank at Outram Park, where donors stream in and out daily.
Every day, more than 300 packs of donated whole blood pass through this facility, which handles all donated blood in Singapore.
Blood comprises three main components: red blood cells, platelets and plasma. A donor can give blood in its entirety - referred to as "whole blood" donation - or only the platelets and plasma.
Donations are, however, entering a seasonal dip. When festive periods roll around, such as the upcoming Chinese New Year next month, blood donations can slide by up to 20 per cent, said the Singapore Red Cross Society.
People could be busy preparing for the celebrations or choose to travel, said its spokesman. "For most people, blood donation may not be on their minds, especially if it's not part of their routine."
In addition, those who returned from countries with known risks of infections, such as Bangladesh and Cambodia, are not eligible to donate blood, he added.
While there is usually enough to tide over these periods, some blood types could hit low levels.
Said an HSA spokesman: "Most of the time, we can meet the minimum required stock. However, the stock of specific blood groups, such as O, tends to fall during festive seasons and long public holidays."
This is because most of Singapore's population are blood type O.
Not only that, type O blood comes in especially handy during emergencies - it is given to patients whose blood types are unknown.
"Therefore, it (type O blood) is more susceptible to fluctuations."
The HSA perennially maintains at least six days' worth of blood in the national inventory "to ensure we have enough blood to respond to any civil or medical emergencies".
Otherwise, most of the red blood cells collected are used within two weeks, said the HSA, though these cells can be kept for up to six weeks.
Fresh frozen plasma can be stored at -35 deg C for up to a year, but platelets last five days at most.
SURGERY TOPS LIST OF NEEDS
The need for blood in Singapore is growing, with demand expected to rise by 3 to 5 per cent yearly in tandem with the ageing population.
But blood donors are getting older too. About 600 regulars stopped donating each year as they succumb to age-related illnesses themselves, according to the Red Cross.
Compounding the problem is the shrinking pool of young donors.
Donors aged 16 to 25 dropped by 13 per cent between 2012 and 2016, based on official statistics.
Despite medical advancements, blood remains crucial in many operations and emergency situations.
It is also a lifeline for people with blood diseases.
In cardiac surgery, for example, transfusions are needed because patients are given blood thinners which make them more likely to bleed, said Assistant Professor Tan Teing Ee, who heads cardiothoracic surgery at the National Heart Centre Singapore.
The blood thinners prevent clots from forming in the heart-lung machine, which temporarily takes over the function of the patient's heart and lungs during the operation.
Surgery such as heart operations form the bulk of medical uses of blood here, at 54 per cent in 2016.
General medicine is ranked second at 31 per cent. Examples are severe bleeding in the gastrointestinal tract and chemotherapy.
About 9 per cent of blood is given to people with blood diseases, while the remaining 6 per cent is used for accidents and emergencies.
Associate Professor Tien Sim Leng, who heads the Singapore General Hospital's (SGH) blood bank, said situations that call for a lot of donor blood are massive trauma from accidents, severe burns and injuries requiring major surgery.
Such cases can "easily use up more than six units of blood" each time, he said. A unit is 250-300ml.
Meanwhile, people with certain blood diseases need regular transfusions of red cells to stay well. These diseases include thalassaemia, aplastic anaemia and myelofibrosis.
"The frequency of blood transfusion for such patients can vary from every few days to weekly, monthly or quarterly, depending on the patient's symptoms and haemoglobin level," said Prof Tien.
Each transfusion is usually one or two blood units, sometimes three, added the senior consultant haematologist who is a blood transfusion specialist.
24 HOURS TO GET BLOOD READY
Getting blood from donor to patient, however, is not as simple as collecting the blood and sending it straight to the hospital.
There are many steps in between to ensure that each unit of blood is a safe match for the patient. Also, patients usually need only specific components of blood, that is, red blood cells, platelets or plasma.
Extracting the platelets and plasma is done by directing blood into a machine, in a process called apheresis donation.
Regardless of the mode of donation, all the collected blood gets separated into red cells, platelets and plasma at HSA.
A small sample from each donor is also taken to be screened for at least five diseases, including HIV, hepatitis B and C, as well as syphilis. Last year, the Zika virus was added to the list.
Ms Sally Lam, laboratory director of blood supply management at HSA, said it takes about 24 hours from the time of collection for blood to be made ready for use.
In addition to the Outram blood bank, there are three other blood banks here - at Dhoby Ghaut, Woodlands and Westgate Tower in Jurong East. People can also give blood at community blood drives.
The blood collected at all these locations is transported to HSA in cooler boxes. Ice packs placed inside the boxes cool the blood along the way, keeping the temperature at about 20-24 deg C .
Ms Lam said the blood labs operate round-the-clock seven days a week to provide a steady supply of blood and respond to emergencies.
In 2016, nearly 1.3 million lab tests were done on about 372,000 blood components at HSA.
For SGH, about 40 per cent of the blood units it receives each year are used by haematology and oncology patients, said Prof Tien.
Among them is Mr Goh Chun Hui, 29, who has undergone "more than hundreds of blood transfusions".
He was diagnosed with severe thalassaemia when he was three.
His bone marrow cannot produce normal red blood cells, so he began going for blood transfusions every two months from the age of seven.
The initial transfusions were "a terrifying experience", said the administrator in the real estate sector.
"The doctors and nurses had to hold me down at the hospital as I was screaming in pain," he recalled.
Over time, Mr Goh got used to the process, although the disease keeps him from strenuous activities. Said Mr Goh: "A lifesaver saves a person once, but the blood donors sustain my life on a regular basis and this enables me to move forward."