Preparation for laboratory tests

2019.06.03

What Do I Need to Know Before Doing a Laboratory Test?

Laboratory testing is a medical procedure that tests samples of blood, urine and other body substances for compliance with established standards and / or properties.

Laboratory tests shall be carried out:

screening to assess for possible changes in human health before symptoms develop;
diagnose, plan treatment, evaluate response to the prescribed treatment, and track disease progression.
Laboratory test values ​​are usually reported as a range, less than one specific number, since normal values ​​vary from person to person. What is the norm for one person may not be the norm for another. Many factors (eg gender, age, race, medical history, general health) can influence the outcome of the study. Sometimes the results of a study are determined by the specific foods, drugs prescribed before the study, and how well they were used. This is why the patient may be asked not to eat or drink for several hours before the examination. In addition, rate values ​​may vary from laboratory to laboratory because assays are conducted using different analyzers, using different methodologies. In order to follow the dynamics of the test, it is particularly important to conduct the tests in the same laboratory. Some laboratory tests (eg, prostate-specific antigen, cholesterol) reveal specific health problems accurately, reliably. Others provide general information to help your physician deal with potential health issues and help you select other tests to diagnose.

Blood test preparation, general requirements:

8 to 14 hours before blood tests. (depending on the type of research you are doing) do not eat, drink juice, tea, coffee, especially with sugar. Drink only water. Eat less fat and fried foods, do not consume alcohol 1-2 days before the test. If there is a feast on the eve of the laboratory test, it is better to postpone the test for 1-2 days. Do not smoke an hour before testing. Many enzymes and hormones in the blood can fluctuate around the clock, so do these tests for up to 10 hours. morning. Avoid sunbathing, exercise (do not exercise) and stress before performing a blood test. Calm and rest for 10-15 minutes before examination.

If you are about to start a medication, you should do the tests before you start taking them, or 10 to 14 days after your medication. Blood tests are usually performed 14 to 21 days after treatment to determine the effectiveness of treatment. Be sure to tell your doctor or laboratory staff if you are taking any medication.

Blood tests after radiography and ultrasound, massage, reflex therapy or physiotherapy are not recommended, and rectal, veloergometric, a biopsy is not possible before blood sampling for PSA and LPSA.
The results of hormonal tests in women are influenced by physiological factors related to the menstrual cycle. Therefore, when preparing for a sex hormone test, you should indicate the phase of the cycle and follow your doctor's recommendation on which day of the cycle you should perform the test.
Prior to the stress hormone test (ACTH, cortisol, prolactin, etc.), it is necessary to calm down, ignore extraneous factors during the procedure, and relax as stress increases the levels of these hormones in the blood.
When examining infections, the developmental stage of the infection and the state of immunity should be considered. If a negative result is obtained, it can not yet be guaranteed that there is no infection. If you are in doubt as to the results of the laboratory tests, it is advisable to retest after 3-5 days. Testing for infectious diseases is best done 21 days after the suspected infection when antibody production is most active.
Patient memo on urine collection:

For all urine tests, morning urine is most appropriate.
A 24-hour urine test is recommended. Do not take vitamin C supplements.
Before urine collection by PCR, do not urinate for 3-4 hours. and do not wash the external genitals.

Urine collection for general urine examination, crop:

Before collecting urine, the genitals are flushed (water only), and women do not need to flush the perineum before urinating.
Collect 100-200 ml middle clean portion of urine in a special jar (available at pharmacies), and urine crop only in a sterile jar (in an airtight container).
The patient's name is written on the jar.
The urine specimen should be delivered to the laboratory within 1-2 hours (if further provided to ensure delivery at +2 to +8 ºC).
Urine collection for the detection of sexually transmitted agents by PCR:

The most suitable test is the "primary portion" of urine.
Collect 50 to 100 ml of urine, starting with the first drops, in a sterile container.
The patient's name is written on the jar.

The sample should be refrigerated and stored at +2 to +8 ºC until delivery to the laboratory.
The urine sample should be delivered to the laboratory within 24 hours.


A sampling of feces:

Fecal samples must be taken from several different places and must be free of urine impurities.
A small amount of feces (about 10 g) is usually sufficient for testing.
Feces following enema, suppositories, suppositories, and other drugs affecting stool formation are not suitable for coprology examination.
No special preparation is required for a general so-called coprologic stool examination.
If the test is for worms, the sampling remains the same, but in the case of excreted feces, they must be submitted to the laboratory together with the fecal sample.


Stool collection for coprology examination

The stools are taken in a special container (container) or a washed glass or plastic container.
The patient's name is written on the jar.
The container should be immediately refrigerated and stored at +2 to +8 ºC until delivery to the laboratory.
The stool sample must be delivered to the laboratory within 24 hours.


Fecal sampling for occult bowel bleeding

It is important that samples are not taken during menstruation or bleeding from hemorrhoids.
The use of fecal sample collectors is recommended to avoid the presence of impurities in urine, blood and toilet water.
Use of anticoagulants, e.g. aspirin or coumarin may lead to higher hemoglobin levels in fecal samples.
High dose iron preparations should be discontinued 1 or 2 days prior to sampling.

Store the tube at room temperature before use.
Take a stool sample using a stool sample collector.
While holding the sample collector upright, open the screw cap.
Remove the spiral wand. Insert the spiral wand into three different areas of the stool sample.
Place the spiral wand along with the stool sample into the sample collector and seal.
Mark the sealed sample collector.
Store the sample collector overnight in a cool and dark place.
The fecal samples in the buffer solution must be delivered to the laboratory within 5 days.


Collection of semen

The results of the male ejaculate test will depend on the method and conditions of collection and delivery to the laboratory and the following requirements must be met during the collection and delivery of semen:

semen is collected after 3-5 days of sexual intercourse masturbation or incomplete sexual intercourse;
5-7 days before examination no prostate massage;
smoking, strong alcoholic beverages, medicines (antibiotics, sulfanyl amides) are not recommended;
no examination if the man is ill or feverish;
do not collect sperm in the condom because the substances in the condom kill the sperm;
the collected ejaculate is delivered to the laboratory without freezing (body temperature).

Semen collection in the laboratory.

The semen is collected in a separate room near the laboratory.
Collect all the sperm in a clean, hand-heated jar with a wide neck;
The patient's name is written on the jar;
Immediately delivered to the laboratory, which records the time of collection of the ejaculate and the number of days of sexual abstinence.