Laboratory test results are involved in about 70 percent of decisions physicians make about how to manage and treat health conditions. Doctors order them as part of a routine checkup to look for changes in your health. Tests are also used to diagnose medical conditions and monitor the progression of a disease.
After taking a sample of your blood, urine or body tissue, a lab technician analyzes the sample to determine whether your results fall within the normal range. Tests use a range to measure results because “normal” varies from person to person, depending on your sex, age, race, diet and medications – and on how well you followed instructions when you prepared for your test.