Live blood analysis practitioners set up in various alternative practices, or even at the local health food store. They'll take some of your blood (or more likely, they give you a sterile pokey thing so that you can do it yourself, since they don't have the necessary qualifications to pierce your skin) plop it on a slide, stick it under a 'scope and then point out imaginary things that require expensive supplements or treatments with a zero-point energy wand.
Wikipedia is uncharactestically blunt in its assessment: "There is no scientific evidence for the validity of live blood analysis, and it has been described as a pseudoscientific, bogus and fraudulent medical test. Live blood testing has also been described as a fraudulent means of convincing a patient that they are ill and require treatment with dietary supplements."
