Frequently Asked Questions
Should I come in on an empty stomach?
It is preferable to come for your tests on an empty stomach, when possible, provided the sample is to be taken early in the morning.
A few tests actually require an absolutely empty stomach starting from the previous evening:
– Cholesterol and triglyceride testing
– Fasting blood sugar tests and insulin tests
– Sedimentation rate tests
– Some functional exams, e.g. Glucose tolerance tests.
Why do I need to be on an empty stomach?
After meals and while digestion is taking place, your blood will carry a number of compounds around the body that come from the digestive process. These include proteins but mostly carbohydrates (sugars) and lipids (fats). Since these compounds are transitory, they should not be present in order to obtain accurate test results.
Also, the presence of chylomicrons (lipoproteins) in the blood give it a milky texture that could hamper the execution of certain dosage methods.
In most people, blood composition returns to normal approximately 2 ½ hours after eating.
With the exception of the tests mentioned above, most tests can be carried out after that time has elapsed.
The Laboratory can perform required for emergency pre-operative tests. Whether the stomach is empty or not will be taken into account when interpreting results.
Ideally, a sample should be taken right before a feeding. If in doubt, please contact us for more information.
Biological tests can be carried out throughout the day – either before a meal, or 2.5 hours after a meal.
Some tests need to be carried out at a particular time of day (cortisol test, for example) or on a particular day of a person’s cycle (FSH, LH, prolactin, etc.).
Your instructions will generally give you all the details you need for such tests.