Blood is a difficult and dangerous substance to clean up. Blood contains many diseases that can be harmful to those cleaning it up. So the answer to this question is to call a professional.
We use specifically designed equipment and chemicals to clean up blood and decontaminate the area. We can typically clean blood out of any area of a home that is not porous and save all structural areas.
Unfortunately, carpet and padding typically have to be removed and disposed of as a biohazard. It really depends on the amount of blood and the material it has contaminated, but most can be cleaned and saved.
Given the dangerous nature of cleaning blood spills yourself, there is no reason to attempt it yourself. Make sure you contact a professional to remove any blood and decontaminate the scene to prevent diseases from spreading.