New figures show almost 40,000 units - around one pint each - of donated blood were wasted in Northern Ireland in the past five years.
Investigative website The Detail reports around 250,000 units of donated blood has been delivered to hospitals across Northern Ireland since 2012, but in the same period around 15% of blood was recorded as wasted.
Blood is considered wasted when it cannot be transfused to a patient for technical reasons which include faults in storage or expiration.
Around 64,000 blood donations are made in Northern Ireland each year, and it is estimated three lives are saved for every pint of blood donated.
In a statement to The Detail, a spokesperson for the Northern Ireland Blood Transfusion Service (NIBTS) said it kept a "buffer stock" of blood as the workload it has to deal with "results in some wastage".
The South Eastern Health Trust is not included in the figures (as they were only able to provide figures for financial years, and not annually) so the overall loss would be higher.
By comparison, blood wastage in Scotland for the period between 2012 and 2017 was almost 11%.
The new figures also show components of blood donations made in Northern Ireland have been sold for commercial use, bringing in almost £500,000.
Blood is made up of different elements including red blood cells, platelets, plasma and red and white blood cells - referred to collectively as blood components.
The liquid portion of the blood known as plasma is removed, and in Northern Ireland a surplus of this accumulates.
The findings show since 2008 this has been sold by the NIBTS to the pharmaceutical industry, with the profits reinvested back into the Department of Health.
Between 2012 and 2016 over 38,000 litres of plasma were sold to Biotech Company Nova Biologics, a US pharmaceutical company, for £442,805.
In Northern Ireland there is an ongoing need for new donors.
Last year NIBTS said it requires 8,000 new donors annually to meet demand, with an estimated three people getting blood transfusions every hour.