blood test

Has anyone's guinea pig had a conscious blood test done please? How was it?

Hello, My guinea pig Tony has been gradually losing weight for a few months now and I’m starting to get really worried. He’s 2.5 years old and now weighs 930g. At his heaviest about a year ago he was 1175g but I didn’t notice he was losing weight until December when he weighed 1090g. I took him...