How to Prepare for a Lab Test Test
Lab tests check your health by measuring substances in your blood, urine, or other samples. How you prepare can affect your results.
What this test measures
Lab tests provide important information about your health. To prepare, you may need to fast or avoid some medicines and activities that may affect your results.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Frequently asked questions
What are lab tests?
Lab tests provide important information about your health.
How should I prepare for a lab test?
You may need to fast or avoid some medicines and activities that may affect your results.
Why is preparation important?
Preparation helps ensure your results are accurate.
Can I take my medicines before a lab test?
You may need to avoid some medicines. Follow your doctor's instructions.
What happens if I don't prepare correctly?
Your results may be affected and may not reflect your true health.
Related lab tests
Sources
- MedlinePlus: How to Prepare for a Lab Test — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.