The ideal fasting period for blood tests is 8-12 hours in normal conditions. Your doctor may also give you specific instructions on whether you need to fast and the fasting period, depending on your clinical condition. The blood tests that require a standard fasting period are:
Prior to sampling, your doctor may warn you about factors that might impact the interpretation of your test results, such as your age, gastrointestinal problems, pregnancy, other diseases, the drugs you use, alcohol intake, severe exercise, and excessive stress. You also should inform your doctor about these factors and discuss, so that they could consider your clinical condition prior to sampling. For example; if you need tests that might be impacted by gastrointesinal problems, you should not have eaten red meat, broccoli or some foods with special ingredients a day before the sampling. If you have such conditions, you should inform your nurse when you come to the laboratory. In general, ideal standard fasting period is 8-12 hours. In addition, you should not drink more than 1-2 glasses of water in the morning of the sampling day, as excessive water may dilute your blood and lead to inaccurate test results. However, standard or slightly above water intake a couple of days before the sampling day will ease the palpation of your veins in drawing your blood sample. You also should not drink coffee or tea before coming to sampling as caffeine in coffee and theophylin in tea might impact some tests. Taking a drugs or vitamins in the morning or the day before, or doing excessive exercise or being under excessive stress may also affect your results. If any of these scenarios apply to you, please inform your nurse so that these conditions can be noted on your results for your doctor’s consideration.
How to prepare 24-hours-urine; Discard the first morning urine. Collect all the following urine into a plastic pet for 24 hours (keep in a cool and dark place with the lid tightly closed). Be careful not to miss any mililiters of the urine you are collecting. Avoid the intake of aspirin, asetaminophene, alcohol, antihistaminics, high amounts of caffeine, vitamins, food that contains vanilla, excessive salt, chocolate, spinach and mineral water before and during the urine collection. Drink water in daily normal doses (~800-2000 ml/day, including foods with water). Excessive water intake would dilute the urine while not enough water intake might result in higher test results. Spot urine samples may also be used depending on your doctor’s instructions.
Semen samples taken in laboratory conditions might result in slightly different results compared to normal coital ejaculation. Minimising these differences would improve the accuracy of the test results. The following factors might affect semen analysis results;
The first fraction of the ejaculate is the most spermium rich portion. Therefore it is important to make sure that portion is not missed to ensure more accurate results.
If there has not been a complete ejaculation during the previous intercourse, the remaining small amount of spermatozoa gets mixed into the following ejaculation. If the sample is given in the following 2-7 days after the last ejaculation, this may not cause a considerable count difference in the number of young and mature spermatozoa. Nevertheless, this information should be shared with the laboratory technician and ensure it is noted on your result sheet.
If the semen will be tested for microbiological analysis the patient should wash his hands and his penis with soap and plenty of water before giving the sample to avoid contamination. If not well rinsed, the soap residue could get mixed into the sample and could kill the bacteria to be inspected, causing a misleading negative test result. The collection cup should be sterile and the time between sample collection and laboratory testing should not be more than 3 hours.
Laboratory sampling is always the most desirable option for fresh specimen. If home preparation is absolutely necessary, ensure that the sample reaches the laboratory in 30-45 minutes the latest. During this period, the sample should be kept at body temperature, between 25-37 degrees (armpit is a good place for transport). If the sample will be brought in a condom, ensure that the condom does not contain any sperm toxic chemicals. Latex condoms are especially unsuitable.
Fasting and a nonurinating period of minimum 6-8 hours is required for whole abdominal ultrasonography, renal doppler and urinary system ultrasonography. Empty your bladder 90 minutes before the test. For pelvic ultrasonography, drink 1 liter of water and do not urinate.
Please visit our Laboratory tests and their interpretations page to learn more about our laboratory tests (sample type, working day, result time, etc).
If you have previous imaging results, please bring them with you. This will enable the radiologist to compare the previous images with their current observations and report the progress of your clinical situation to your doctor.
Please try to attend your appointment a little earlier than your scheduled time. This will allow you to have time to get ready for the examination, and give your radiologist extra time to examine you, especially if the previous appointment has been completed earlier.