MODEL RELEASED. Blood testing. Medical laboratory worker using a computer to find the details of the blood samples she is holding. The labels on the samples allow them to be tracked through the highly automated processes used to analyse them. Barcodes and scanners are often used to reduce errors when entering the sample data. The samples can then be selected on a screen. Blood is analysed for a wide range of things, including bacterial infection and levels of gases, sugars, and electrolytes.