Wednesday, 24 January 2018

Where does your donated blood go?

Keeping donor blood flowing in Singapore amid seasonal dip
Every day, hundreds of blood units are given to the sick and injured across Singapore. Before donated blood reaches the patient, however, it passes through many steps - a process that is kept up even during seasonal dips in blood donation. Here is a look at what goes on behind the scenes, how the national blood supply is maintained, and key facts about blood and its medical uses.
By Poon Chian Hui, Assistant News Editor, The Straits Times, 23 Jan 2018

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."





Questions you may have about blood... answered
What sets apart a person with O-positive blood from someone with AB-positive blood? And what happens if your donated blood is found to carry a disease? These are some questions people may have on blood and its uses, and here are the answers, verified by the Singapore Red Cross Society and the Health Sciences Authority (HSA).
By Poon Chian Hui, The Straits Times, 23 Jan 2018


Q ONE UNIT OF YOUR BLOOD HAD BEEN COLLECTED AT THE BLOOD BANK. HOW MANY LIVES CAN BE SAVED WITH THAT SINGLE PACK OF BLOOD?

A Three. Every pack of blood gets separated into three parts: red cells, platelets and plasma. Each can be used for different medical issues.

Red cells can be given to someone undergoing an operation; platelets can help those with dengue fever; while plasma is a lifeline for people with disorders that prevent blood from clotting properly.


Q IT IS AN EMERGENCY! A MAN HAS BEEN IN AN ACCIDENT AND NEEDS BLOOD URGENTLY. BUT HIS BLOOD TYPE IS UNKNOWN. AT THE HOSPITAL, WHAT BLOOD TYPE WILL HE BE GIVEN?

A Doctors will transfuse type O blood for him - also known as the emergency blood type. It is also the most common blood type in the Singapore population.


Q YOUR BLOOD GROUP IS AB-POSITIVE. WHAT OPTIONS DO YOU HAVE, IN CASE YOU NEED A TRANSFUSION?

A As the universal recipient, you can receive red blood cells of any blood group. However, there is more to it than just the ABO blood group system. Every blood recipient will also be screened for red cell antibodies, which also play a role in the matching process.

The accompanying table shows the general compatibility of the ABO blood types.


Q YOUR NATIONAL REGISTRATION IDENTITY CARD (NRIC) ALREADY STATES YOUR BLOOD GROUP IS O-POSITIVE. WHEN DONATING BLOOD, CAN THE BLOOD GROUP TESTING BE SKIPPED?

A There is a chance that the blood type stated on your IC is wrong. The donor's blood group is tested using a highly accurate method regardless of the information on the IC. Since late 2002, the new NRIC no longer bears the blood group information.


Q BUT WHAT IF YOU ARE NOT A FIRST-TIME DONOR?

A Even if you have given blood dozens of times, your blood group will be tested every time for safety and compatibility.


Q YOU ARE A 16-YEAR-OLD STUDENT WHO IS KEEN TO DONATE BLOOD. BUT SOME WEBSITES STATE THAT DONORS ARE USUALLY 18 TO 60 YEARS OLD. DO YOU HAVE TO WAIT?

A One can give blood from the age of 16. But youth aged 16 and 17 require the approval of a parent or guardian. They will need to hand in a signed parental consent form when they show up to donate blood.


Q CAN DONATING BLOOD HELP YOU TO LOSE WEIGHT?

A No, it does not. While there may be mild transient weight changes after donating blood, the fluid lost will usually be restored by the body within the next 12 to 24 hours.


Q SOME HOSPITALS ARE FARTHER FROM HSA THAN OTHERS. HOW IS BLOOD TRANSPORTED FROM PLACE TO PLACE, AND KEPT AT IDEAL TEMPERATURES?

A Donated blood and blood products are transported in insulated cooler boxes, like the kind used to keep drinks cold. But these boxes have been "validated" as having the optimal quantity of cooling material needed for an ideal temperature to be maintained till the blood components reach their destination.


Q YOU INDULGED IN A FAST-FOOD FEAST LAST NIGHT. WHY IS IT NOT A GOOD IDEA TO DONATE BLOOD THE NEXT DAY?

A A heavy, fatty meal causes the amount of fat in the circulatory system to rise temporarily. This makes the plasma in the blood cloudy, which may, in turn, interfere with laboratory test results.

The tests usually rely on optical density, so cloudy plasma could give a false positive - when the result states a disease is present in one's blood, when it is actually not.

In fact, any oily food can throw a spanner in the works. So, take a light meal before you donate blood.





Q WHEN PATIENTS RECEIVE BLOOD, THEY PAY A FEE. CAN YOU GET PAID FOR GIVING YOUR BLOOD TO THEM?

A No. Blood donation is voluntary. If donors are paid, it may spur people to give blood for the wrong reasons, or even withhold important health information - for instance that they have a sexually transmitted infection. This will affect the safety of their blood.

The fee that patients pay, on the other hand, is not for the blood itself, but for the processing of blood. It includes laboratory testing for infections and transport costs.

This fee is subsidised by the Government and hospitals for Singapore citizens and, to a lesser extent, permanent residents. The hospital subsidy differs based on the choice of ward and means-testing status.


Q IF YOUR DONATED BLOOD TESTS POSITIVE FOR A DISEASE AT THE LAB, WILL YOU EVER KNOW?

A Yes. All donated blood is tested for at least five infections: HIV, hepatitis B and C, syphilis, as well as Zika. If your blood shows signs of any of these diseases, the blood bank will contact you to inform and advise you if further medical care is required.





Preserving rare blood types for a rainy day
Extending shelf life important, as only 1.5 per cent of donors in 2016 had negative blood types
By Poon Chian Hui, The Straits Times, 23 Jan 2018

Every drop of blood is precious, but they are not quite equal.

Some blood types can be hard to come by. For every 1,000 people who give blood in Singapore, only one person carries the AB negative blood type (0.1 per cent).

In general, donors with negative blood types are rare, forming only 1.5 per cent of the total pool in 2016.

To keep some of these for a rainy day, the Health Sciences Authority's (HSA) blood services group deep-freezes the red cells of rare blood types at -80 deg C.

This way, the red cells' shelf life can be extended from the usual 42 days to 10 years, said Ms Sally Lam, laboratory director of blood supply management at HSA, which runs the national blood service.

Otherwise, red cells are kept at 1 deg C to 6 deg C in fridges or cold rooms.

Platelets are kept at 20 deg C to 24 deg C in large incubators with trays that gently rock back and forth, for up to five days. Ms Lam explained that platelets need to be "agitated" constantly, or they would clump up.

Plasma is quick-frozen and refrigerated at -35 deg C for up to a year.



Only blood that gets the all-clear after laboratory tests are stored, said HSA. Blood that is unsuitable for use will be disposed of properly.

The rejection rate is low - less than 3 per cent to 4 per cent of all donated blood components. Some reasons for rejection include a positive result for an infection or that the plasma was too fatty.

Donors can also ask the HSA to retract their blood through a 24-hour call line. They do not have to give a reason for making such a request.

At hospitals, there are measures to ensure blood products are used properly and wastage is minimised.

Singapore General Hospital, for instance, has a guideline on the number of blood units required for each specific procedure, said Associate Professor Tien Sim Leng, who heads the hospital's blood bank. "To minimise wastage, blood is issued only when the patient is in the operating theatre and needs blood."

Medical institutions such as those under the SingHealth group, which includes National Heart Centre Singapore (NHCS), also have a committee overseeing blood transfusion.

Assistant Professor Tan Teing Ee, director of NHCS' cardiothoracic surgery intensive care unit, added that blood transported to the operating theatre is kept in fridges there and "will not be taken out unless it is meant to be used".

"If the blood product is out of the refrigerator for too long, it cannot be returned and thus has to be discarded," he explained.

If the blood in the refrigerator remains untouched after an operation, it will be transported back to HSA to be crossmatched to other patients.

"We try to minimise the use of blood products in surgical procedures... as blood transfusion carries risks," Prof Tan added.

Taking supplements and stopping blood-thinning medication before surgery are some ways to help to reduce patients' need for transfusions.

Prof Tan noted that expired blood, unfortunately, has to be thrown away. "This is sometimes unavoidable on days when there is more donor blood than what is required."


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