There are many factors that determine the cost of a lab test, including the type of test, where the test is performed, and if you have insurance coverage. When prescribed by a doctor, testing is often covered if you have insurance, but you may still have a copay or deductible. There can also be fees charged by the technicians who draw your blood. Point-of-care testing at health fairs is usually done at no charge or very low-cost. Check with your doctor and insurance plan about the cost of your test.