Blood transfusion is a common life-saving procedure, with an estimated 14 units of blood used per hour in Singapore. KK Women’s and Children’s Hospital (KKH) is maintaining constant haemovigilance to prevent patients experiencing potential adverse reactions to the very substance that is meant to save lives. KKH is maintaining constant haemovigilance to prevent patients experiencing potential adverse reactions to the very substance that is meant to save lives.

In Singapore, an estimated 160,000 units of blood was transfused every year from 2013 to 2016. The blood and its vital components – including red blood cells, platelets and plasma – are used to sustain patients during general surgery, and during the treatment of medical conditions such as haemorrhagic fever and cancers, blood diseases such as thalassaemia, and trauma sustained through accidents and emergencies.

Donated blood is processed and tested at the Health Sciences Authority (HSA) laboratories before it is transfused to patients. Stringent donor screening and testing of donor samples are also carried out. Thus, the risks of acquiring transfusion-transmitted viral infections such as Hepatitis B, Hepatitis C or the Human Immunodeficiency Virus are almost negligible, in the order of 0.001 to 0.00015 percent.

Nevertheless, similar to most medical procedures, blood transfusion carries some unavoidable risks – after a blood transfusion, a patient may experience an adverse transfusion reaction. This is an undesirable response that is related to the administration of a blood product such as red cells, platelets or plasma.

At KK Women’s and Children’s Hospital (KKH), which manages high risk conditions in women and children, haemovigilance is observed – where a set of surveillance procedures is established to collect and analyse information on adverse incidents related to blood transfusions. This allows for identification of transfusion hazards and areas of practice where key improvements can be made to reinforce patient safety.


Early recognition and prompt management

Adverse transfusion reactions can be acute and present within hours of a blood transfusion, or be delayed up to four weeks after a transfusion has taken place. Collating nationwide statistics, the Blood Services Group noted that approximately 600 to 700 adverse transfusion reactions were reported annually by the blood banks of restructured hospitals during the same period. This translates to a low annual incidence of less than 0.5 percent of all transfusions in Singapore.

While adverse transfusion reactions cannot be completely predicted or prevented, early recognition and prompt management of these reactions are key to the successful management of outcomes in patients.

Following Clinical Practice Guidelines by HSA and Ministry of Health (MOH), when a transfusion reaction is suspected at KKH, the transfusion will be stopped immediately while intravenous access is maintained with normal saline. The patient’s vital signs are carefully monitored and appropriate treatment will be instituted.

Concurrently, an investigation of a suspected transfusion reaction will be conducted, starting at the bedside with a repeat check of the patient’s identification against the unit of blood and transfusion slip to rule out patient misidentification.

The hospital’s blood bank will also be notified of the suspected transfusion reaction. Blood samples from the patient may be requested for further investigation, and the affected unit of blood will be returned to the blood bank.

As many of the initial signs and symptoms of a transfusion reaction can be nonspecific, it is important for healthcare providers to be mindful of these differentials and continue to follow up with patients after their transfusion to promptly recognise and react to potential transfusion reactions.

Blood transfusion recipients should also seek medical help if they develop unexpected symptoms in the hours and days following a transfusion.

Case study: A transfusion that left a patient breathless

Four-year-old Jessica (not her real name), who was diagnosed with Stage 4 neuroblastoma, had received multiple transfusions of blood products without incident. Following a course of chemotherapy, she was admitted for a routine platelet transfusion.

Four hours after the successful platelet transfusion, Jessica became progressively breathless with an abnormally fast heart rate. While she had no associated fever or cough, her oxygen saturation decreased to 75 percent on room air, warranting a transfer to the Children’s Intensive Care Unit for further management of her symptoms.

Differentials which were considered included infection, fluid overload and acute pulmonary embolism. A chest X-ray taken during the episode showed bilateral lung infiltrates. Her electrocardiogram result was normal and an echocardiography showed normal cardiac function without any signs suggestive of fluid overload.

In view of the recently completed platelet transfusion, a diagnosis of transfusion-associated acute lung injury (TRALI) was suspected and treatment was promptly administered. Jessica responded well to supportive therapy, which included non-invasive ventilatory support, and made a full recovery.

Subsequently, the suspected transfusion reaction was reported to KKH’s blood bank, leading to the discovery of Anti-HLA antibodies implicated in TRALI in the donor’s plasma through a test. All blood products from the donor were discarded, and the donor was advised to refrain from further donations to prevent recurrence of this transfusion reaction in other recipients.

Saving lives one drop at a time

While blood transfusion reactions are not able to be completely predicted or prevented, it is reassuring that the incidence of adverse transfusion reactions in Singapore remains very low.

Many lives continue to be saved by blood donations every year. The volume of blood needed for transfusions in Singapore is estimated to increase by three to five percent annually as the needs of the local population evolve. Concurrently, a rising number of blood donors are stepping forward due to increasing awareness of national blood needs.

KKH continues to partner with HAS and MOH in maintaining haemovigilance, to ensure a safe and adequate blood supply for all patients who need a transfusion.

To find out more about blood donation, or to give blood to help save a life, please call +65 6220 0183 or visit

​Dr Joyce Lam, Senior Consultant, Haematology/Oncology Service, Department of Paediatrics Subspecialties, KK Women’s and Children’s Hospital

Dr Joyce Lam leads the haematology laboratory and blood bank at KKH, and her clinical and research interests include paediatric bleeding disorders and diagnostic aspects of paediatric haematology.



  1. American Association of Blood Banks Technical Manual, 18th edition, 2014. Eds Mark Fung, Brenda Grossman, Christopher Hillyer, Connie Westhoff.
  2. HSA-MOH Clinical Practice Guidelines 2011. Clinical Blood Transfusion.
  3. HSA Haemovigilance Data, 2013 - 2016.
  4. Health Sciences Authority. (2016). Blood Connects, Donors Unite [Press Release]. Retrieved from