BEFORE YOUR SAMPLE COLLECTION
What to know before your visit
Some laboratory tests require specific preparation, such as fasting, avoiding physical activity or collecting a sample at a certain time of day.
Please follow the instructions given by your doctor, the laboratory or the collection centre. If you are unsure what applies to your test, ask before your appointment or before collecting your sample at home.
BLOOD TESTS AND URINE SAMPLES
How to prepare
Fasting
For some blood tests or urine collections, you may need to fast for 8 to 12 hours before your appointment. This means you should not eat or drink beverages containing sugar or fat during this time. You may usually drink water, unless your doctor or the laboratory has told you otherwise.
Timing of the sample
Whenever possible, blood samples should be taken in the morning, ideally between 7:00 and 9:00. Many reference values are based on morning samples taken while fasting. Some hormones and other laboratory values can also change during the day.
If your sample cannot be taken in the morning, the collection time should be noted on the request form so that it can be considered when interpreting the result.
Stress and physical activity
Try to avoid stressful situations before your blood test, as stress can affect certain laboratory values, including stress hormones.
Avoid intense physical activity immediately before your blood test. Muscle activity can affect certain values, such as creatine kinase and other muscle-related parameters. It can also have short-term effects on the blood count and, in some cases, urine values.
Medical examinations before the blood test
Certain examinations or procedures can affect laboratory values. These should usually be carried out after the blood test, not before.
This includes examinations such as breast or prostate palpation, exercise ECGs, punctures and similar procedures.
SPECIFIC TESTS
Some tests need extra preparation
For certain analyses or urine collections, you may need to follow specific instructions for a few days before the sample is collected.
Depending on the test, this may include avoiding certain foods, drinks, nicotine, alcohol or supplements.
Examples include:
For some hormone-related analyses, such as vanillylmandelic acid, adrenaline or noradrenaline measurements, coffee, tea, alcohol and nicotine may need to be avoided.
For oxalic acid measurement in urine, vitamin C should not be taken during the 24 hours before urine collection.
For hydroxyindoleacetic acid measurement in urine, bananas, avocados, aubergines, pineapple, tomatoes and nuts should be avoided for two days before urine collection.
Always follow the instructions provided for your specific test.
FOLLOW-UP TESTS
Keep conditions as similar as possible
If you have tests that are repeated regularly over time, try to have your samples taken at the same time of day and under similar conditions whenever possible. For example, blood samples should ideally be taken in the same position each time, either sitting or lying down.
Keeping the conditions similar can help your doctor compare results more reliably over time.
HOME COLLECTION
Before collecting a sample at home
Before collecting a urine or stool sample at home, please make sure that:
You understand the collection procedure.
You have received clear instructions.
You know which container to use for each sample.
You know when and where to return the sample.
Using the correct container is important. If the wrong container is used, the sample may not be suitable for analysis and a new collection may be needed.
If you are unsure how to collect your sample, contact your doctor, the collection centre or the laboratory before collecting it.
Frequently Asked Questions
In many cases, yes. For a blood test or urine collection, you may be asked to fast for 8 to 12 hours beforehand. This means you should not eat or drink beverages containing sugar or fat during this period. You may usually drink water, unless your doctor has given you different instructions.
Most reference values are based on blood samples taken in the morning while fasting. Some hormones and other laboratory values can vary throughout the day, so taking the sample in the morning helps ensure more accurate interpretation of the results.
If your blood sample cannot be taken in the morning, the collection time should be noted on the request form. This allows the laboratory to take the timing into account when interpreting your results.
Yes. Stress can influence certain laboratory values, including stress hormones and other analyses. For this reason, it is recommended to avoid stressful situations before your blood test whenever possible.
Yes. Physical exertion shortly before a blood test can affect certain results, such as creatine kinase, muscle-related parameters, blood count values and, in some cases, urine values. It is best to avoid intense physical activity immediately before the sample is taken.
For some specific analyses, you may need to follow dietary restrictions for a few days before the sample is collected. For example, coffee, tea, alcohol and nicotine may need to be avoided for certain hormone-related tests. Other tests may require avoiding foods such as bananas, avocados, aubergines, pineapple, tomatoes or nuts. Please follow the instructions provided by your doctor or laboratory.