If you've ever had to give a tube of blood or a little cup of urine in your doctor's office, you've had a laboratory test. Laboratory tests check a sample of your blood, urine or body tissues. A technician or your doctor analyzes the test samples to see if your results fall within the normal range. The tests use a range because what is normal differs from person to person. Many factors affect test results. These include- Your sex, age and race
- What you eat and drink
- Medicines you take
- How well you followed pre-test instructions
