Instructions for patients before blood tests – adults

Please follow the instructions strictly! Only in this way can we receive reliable, non-falsified data. If in doubt, please contact our laboratory or consult your doctor.

The instructions do not cover emergency situations (life- or health-threatening).


Blood sampling shall be done:

  • In the morning, 8 or 12 hours after your last meal, which means that you should not eat anything or drink any juice, sweet beverages, coffee or tea;
  • Whilst maintaining normal diet – besides the 8-12-hour break stated above, fastening the day before blood tests is contraindicated;
  • If possible, before taking drugs (unless otherwise decided by your doctor);
  • After a good night sleep;
  • If during the past 8-12 hours before the test you are thirsty, you should drink small quantities of still water – 1 glass of water after waking up is recommended.
  • Physical exercise should be limited 24 hours before the tests, and in the case of a long-lasting physical exercise, such as: running the marathon, hard physical work, all-night party, you should wait 3 days before the blood test.
  • Long, hot baths before blood tests should be limited.
  • Limiting alcohol 24 hours before the blood tests, and if alcohol is consumed in large quantities, you should wait 3 days before the blood test.


  • You should have your tests done in the morning, before your meal.
  • You should drink a glass of still water before the test.
  • On the preceding day you should be on a light, low-fat diet.
  • You should limit physical exercise and stress 24 hours before blood test.
  • You should not have your tests done during or right after an infection.

BLOOD GROUP (scheduled before surgery)

  • We kindly request that you come for the test min. 7 days before the planned surgery if the date of the surgery is distant.


  • You should not have a sexual intercourse, avoid prostate massage and any physical activity that may affect that organ for 48 hours before the test.


  • The test is done after a good night sleep.
  • You should not be stressed out and avoid physical exercise during the last 24 hours before blood test.
  • You should not have your hormonal tests done during or right after an infection.
  • Hormones should be determined at a specific time of the day (if possible – in the morning) due to the variable daily pattern of many hormones.


  • During the test, you should avoid physical exercise and stay at the laboratory/sampling point.
  • After the first test you will receive a solution of 75g glucose, followed by blood sampling – 1 hour and 2 hours after drinking up the solution.
  • You should not eat food or drink sweet beverages.
  • The test should not be done during or right after an infection.


After blood sampling, you should continue to press the swab against the injection site ca. 5 minutes, as this will minimize the risk of painful bruises at the injection site.

Should you have any doubts or need additional information concerning the preparation for specific tests, please contact the laboratory staff by calling (22) 781 01 67.