Standard blood collection tubes withdraw up to 6 millilitres of blood for tests in intensive care
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Using smaller vials to collect blood samples from people in intensive care could help prevent risky transfusions and improve patient outcomes. This simple change has the potential to lower the risk of complications and preserve valuable supplies of donated blood.
Currently, most hospitals use standard blood collection tubes that withdraw 4 to 6 millilitres of blood when conducting tests on patients in intensive care units (ICUs). However, most of these tests, which include checking organ function, clotting, and respiratory health, only require less than 0.5 millilitres of blood.
Collecting unnecessarily large blood samples in ICUs can lead to significant blood loss and anaemia as multiple samples are taken from patients daily.
According to Deborah Siegal, a researcher at the University of Ottawa in Canada, “After eight days in intensive care, the amount of blood loss is equivalent to donating a unit of whole blood [around 350 to 525 millilitres]. Unlike healthy blood donors, ICU patients are often unable to produce more red blood cells to correct for this blood loss.”
Approximately 40 percent of people in intensive care require blood transfusions, often due to their illness or injuries. Taking unnecessarily large blood samples exacerbates this need and puts a strain on the limited supplies of donated blood, leading to potential allergic reactions and infections.
To address this issue, Siegal and her colleagues conducted a study involving over 27,400 adults who had been in intensive care for at least two days at ICUs across Canada.
During the study, two of the units switched to using smaller vials that collected between 1.8 and 3.5 millilitres of blood, while the other units continued using standard test tubes. The team analyzed the number of transfusions given and found that using smaller vials could prevent one transfusion for every 10 people in intensive care compared to using standard tubes.
Over the course of the nearly two-year study, this change could save about 1500 units of blood and also seemed to reduce the risk of anaemia.
The use of smaller vials did not affect the quality of blood tests and they are commercially available at the same cost and physical size as standard-volume tubes, making them easily implementable with existing lab equipment.
