From Dr Google...
Some common recommendations for blood testing:
Some thyroid medications, such as levothyroxine, should be taken at least 4 hours before the blood test to avoid affecting the results.
Oestrogel: It is best to follow the advice of your healthcare provider regarding when to take the medication before the blood test. Some healthcare providers may advise you to take the medication as usual before the test, while others may advise you to skip the dose before the test.
If you have any questions or concerns, you should discuss them with a healthcare provider.