When taking a blood sample, it is necessary to stop the blood from clogging, coagulating. To do this, you add a substance to the blood inside a tube and turn it several times to mix. Earlier, this was done by hand and if it wasn’t done properly, the test could not be used.
The nurse Barbro Hjalmarson invented a blood cradle to make this procedure easier. The blood cradle works on batteries and rocks the test tubes to mix them correctly.
She took out a patent for it in 1994 and her blood cradle is used in Sweden and in the other Nordic countries.