Blood test preparation

Preparation is required for most blood lab tests, which involve a sampling collection in the morning (on an empty stomach), 12 hours after the last meal. This is necessary because food consumption in the time period before blood collection can cause a rise in the concentration of glucose, cholesterol, lipids, proteins, iron and other metabolites in the blood.



Physical activity should be avoided prior to drawing blood because it can raise the levels of some specific enzymes (eg. CK and LDH)

It should be noted that blood draw for prolactin, cortisol, ACTH, and catecholamines, must be performed in a state of complete relaxation and resting (lying down) from 20-30 minutes. These hormones have significant daily variation i.e. the time of the blood draw and hormone analysis should be determined by a physician.

It is recommended for patients receiving an ORAL ANTICOAGULANT therapy that the blood test is done in the morning hours. After the test they can continue with their usual therapy. This also applies to patients who take therapy for chronic diseases.

In order to obtain reliable results, in consultation with your physician, the blood test should be performed after therapy termination and washout period (the time required for the body to clean the system of certain medication ) – this particularly refers to iron and hormone therapy, vitamin supplements, etc.


For urine and/or urine culture analysis, the first morning urine is collected (midstream specimen), necessary after performed personal hygiene (using warm water and soap), gathered in a sterile container and delivered to the lab as soon as possible. If you are not able to come to the lab right away, place the urine in a refrigerator. The specimen should, however, be delivered to the lab within two hours of collecting or within four hours at the latest if it was refrigerated.

For the analysis of 24 hour urine (all day urine test) you should drink 6 to 8 glasses of water (about 1.5 L). Urine can be collected in a clean plastic bottle (preferably from bottled water). On the first morning of urine collection, first completely empty the bladder, discard that urine and write down the time. Collect ALL urine samples during the day and night in a plastic bottle. Exactly 24 hours after the beginning of the collection, completely empty the bladder and add that urine to the collected urine. This last sample completes your 24 hour urine.


Тhe glucose tolerance test is performed in the laboratory and lasts 120-180 minutes (depending on your physician’s recommendation). During the test, the patient should rest and cannot eat, drink, or smoke. A few days before the test is performed, the patient should be on a balanced diet and should not be under excessive physical strain. The patient should stop taking certain medication that could affect the glucose metabolism (ex. Corticosteroids), but only in consultation with a physician.

Patients’ preparation for the sample collection for microbiological tests is particularly important, because it can significantly affect the results of the examination. All samples should be taken before starting of antibiotic therapy or a few days (at least 48 hours) after terminating it.

Urine culture is the most common analysis in microbiology. Preparing for urine collection for the urine culture test is especially important for women and young children. It is necessary to carefully wash the external genitalia with lukewarm water and soap, so that the water stream flows from the front towards the back. Afterwards, the skin needs to be dried, without applying any creams. The preparation for urine collection for the urine culture test for men also includes cleaning the genitals with lukewarm water and soap. Particular attention should be given to children, so that the foreskin should be pulled back and washed. Since the first stream of urine virtually washes out the bacteria from the skin and bacterial flora of the urethra, the midstream is what should be collected in a sterile container and it is sufficient to fill it to a third of its volume. In children it is also advisable to ensure that they urinate directly into the sterile container, but if this is not possible, you should also wash their external genitalia, place a little plastic bag and control when the child urinates. Then you should remove the plastic bag and bring it to the lab.

When possible, the urine sample should be taken in the morning, so that the patient does not urinate overnight before giving the urine sample. Given that urine is a good environment for bacterial growth, the urine should be delivered to the laboratory quickly or it should be refrigerated until taken to the laboratory. In case genital hygiene hasn’t been performed properly or if the urine was left on room temperature for prolonged periods of time, many bacteria from skin, vaginal or intestinal flora will show up in the urine culture.

For determining the presence of chlamydia, mycoplasma or ureaplasma in urine, it is necessary to collect the first urine stream (first morning urine), which usually contains epithelial cells of the urethra where these microorganisms are present. This particularly refers to men, because in women, a cervical smear is performed in order to isolate these microorganisms.

In case of a possible urethritis, regardless whether it is caused by bacteria, chlamydia, mycoplasma or ureaplasma, a urethral swab is taken in the morning and before urinating; if that is not possible, then anytime during the day, however it has to be taken at least 2 hours after the last urination.

A pharynx (throat) swab should be taken in the morning before brushing teeth or consuming food or water. In case the swab needs to be taken during the day, 2 hours after the last meal or drink have to pass.

Nasal swab should be taken before starting an antibiotic therapy and at least 3 to 4 hours after the last rinsing (blowing) of the nose. Ideally, for microbiological examination, nasal secretion should be collected, especially if thick and stained, because it indicates a bacterial infection, as oppose to the transparent and watery secretion usually accompanying a viral infection.

In children, when taking a throat or nasal swab, parents should hold the child in their lap, placing one arm over both of its arms, and the other arm placed over its forehead, holding the head, while the medical person takes the swab.


Sputum (phlegm) for microbiological analysis is best taken in the morning, before consuming any food or before rinsing the mouth with disinfectants, and equally important, before starting an antibiotic therapy. Previously, the mouth should be rinsed with regular water, which should be then spit out, and afterwards the patient should deeply cough up as much sputum as possible into a sterile container. Along with the sputum analysis, an oral cavity swab should be taken, too. There are certain criteria, which on the basis of microbiological tests of the sample under a microscope, conclude whether the sample is adequate; that is whether instead of bronchial secretions, a saliva sample is collected, and such sample cannot yield a valid result, so it should not be considered.


Genital swabs

›          Vaginal and cervical smears (the patient should not have sexual relations 24 hours before taking the smear).

›          Urethral swab (the patient should not urinate at least 1 to 2 hours before taking the swab).

For sperm culture analysis, the patient needs to urinate before giving a sperm sample.