Barbro Hjalmarsson was a nurse, healthcare teacher and inventor.

Barbro Hjalmarsson was born in 1919 in Viby parish in the province of Närke. During the whole of her professional life, she worked as a nurse and healthcare teacher in what is now Region Stockholm. Apart from that, she was an inventor who created products and methods that came to change how healthcare personnel all over the world analyse blood samples.

Barbro Hjalmarsson’s first innovation was a method for measuring blood sedimentation, which is done to find out whether or not there is inflammation in a body. According to her method, blood is tapped into a test tube with a special additive in it that makes the blood cells separate out from the blood plasma. Depending on how quickly the blood cells sink to the bottom, it is possible to assess whether or not there is an inflammatory reaction in the body. The plasma that collects above the blood cells is thereafter measured to give the degree of inflammation.

Barbro Hjalmarsson’s second invention, Triomix, emerged from a real and self-experienced need. In her work as a nurse, she experienced how stressful it was to take blood tests since each blood test had to be turned 10—15 times so that the blood could be mixed with an anti-coagulation liquid. If this was not done properly, the tests might be destroyed, with inaccurate analyses and diagnoses as a result. To solve this problem, Barbro Hjalmarsson, in cooperation with Triolab AB constructed the battery-driven blood cradle Triomix. In it, six to ten test tubes could be mixed simultaneously in a cradle that rocked back and forth. With 1.5 volt batteries, Triomix could be used for 250 hours in a row.

Triomix began to be manufactured in 1988, but was first patented in 1994 under the description “mixing apparatus including one mixing cradle for placing test tubes, made to move with a rocking motion of a certain frequency”. Barbro Hjalmarsson was then 75 years old, and despite her inventions she is still relatively unknown. Triomix was sold by Barbro Hjalmarsson to Triolab that nowadays sells this blood cradle all over the Nordic countries. Her method for determining blood sedimentation is still in use all over the world.

In 2008, Barbro Hjalmarsson was given attention in an exhibition of women inventors at Tekniska Museet in Stockholm, which she herself was able to visit when she was almost 90 years old. She died in 2012 in Degerfors, at 93 years of age.