How do I prepare for my laboratory tests?
Some laboratory results can only be used if you have prepared properly.
Fasting
Many blood tests have to meet certain conditions to be meaningful. For analyses such as blood lipids, sugar, acid–base balance or dark-field microscopy, you must come "fasting".
So what does fasting mean...
- Solid food may only be eaten until midnight the day before.
- After that, drink according to your thirst. You should not arrive "dehydrated" – but do not overdo it either.
- Only water is allowed – at body temperature. A little unsweetened tea, but no strong herbal teas.
- Coffee is not allowed
Tea often contains more caffeine than coffee, and sweeteners are also not allowed (especially for the glucose tolerance test and insulin test).
Medication
- Only take essential medicines before the blood test; take the others afterwards. You can bring them with you for this.
- Supplements should be stopped at least 3 days before the laboratory appointment.
Sport
- Avoid morning exercises and all strenuous activity.
- And do not cycle to the practice.
The most important general medical analyses requiring a fasting blood sample without prior physical over-exertion:
- Basic metabolism: glucose, liver and blood lipid values, muscle enzymes, uric acid/urea, lactate or EPOC
- Special metabolism / endocrinology: hormone profiles, OGTT, insulin tolerance test, Synacthen test
Smoking
Tobacco or other nicotine products should also not be used after midnight.
Bladder
Depending on the tests, it can be helpful to leave some urine in your bladder.
Illness
If you have a cold or another acute illness unrelated to the condition being investigated, it is advisable to postpone the blood test until the symptoms have completely gone.
Laboratory – information
What do my values mean?
Don't panic about the red numbers! Laboratory results have to be looked at individually. Don't let the colours mislead you!
Thyroid analysis and biotin
For thyroid values to be measured correctly, the supplement biotin must be stopped 3 days before the blood test, because biotin is also used in measuring the hormones.
Preparing for a hormone blood test
Correct preparation is crucial for a meaningful hormone measurement.
Hormone creams, gels or solutions (e.g. with oestradiol, progesterone or testosterone) must not be applied to the crook of the elbow or the forearms, as this can lead to falsely raised laboratory values.
Please therefore note:
- On the day of the blood test, do not apply hormone preparations to your arms or near the puncture site
- Ideally, the last application should be at least 24 hours before the blood test
- Alternatively: apply to parts of the body that are not used for taking blood (e.g. the thighs)
- If possible, the blood should be taken before the next application
Even if the skin is cleaned carefully, residues can remain and distort the measurement.
If you are unsure, please speak to us before the blood test.
The OsteoTest
The OsteoTest determines whether bone metabolism is building up or breaking down bone. This analysis is very new, so there are still few long-term data. For this reason, classic markers such as CTX or procollagen usually have to be used as well.
During treatment, the OsteoTest is used to evaluate whether a measure improves bone metabolism.
The calcium isotope composition is determined in the blood samples.
Carrying out the OsteoTest
The blood must be taken in the morning, fasting. In addition, any sporting activity before the test is prohibited.
You will receive a form with further instructions, namely:
IMPORTANT
After the blood test you must complete an online form (in German)
Without this information, the results will not be released!
Where it says "Barcode", enter the number (letters and digits) shown on the tube (see picture below). We will give you this tube when your blood is taken.
Please pay attention to upper and lower case
The result is available after about 1 week.