Here are the general rules and specific guidelines for various blood tests:
General rules for preparation for any blood tests:
- Collection is done on an empty stomach.
- Last meal: 3-5 hours for children under 1 year, 2 hours for other ages, and 8-12 hours (12 hours for lipid spectrum studies) before blood collection.
Drink no more than 200 ml of non-carbonated drinking water (exclude tea, coffee, juices, etc.) for all types of blood tests, except glucose.
Restrictions:
- Fried and fatty foods: do not eat 2 days before the test.
- Alcohol: do not consume alcohol 24 hours before the test.
- Tobacco: do not smoke one hour before the test.
- Strong physical activity: exclude 3 days before the test.
- Medications, dietary supplements, sports nutrition: stop taking 14 days before the test.
- High doses of biotin (more than 5 mg/day): do not take 8 hours before the test.
Recommendations:
- Rest for 15-20 minutes before taking the test at the blood collection point.
- Repeat the test at the same time, in the same position, and in the same laboratory where you had the test before.
- If you take medication only at a certain time in the morning, it is better to do it after the blood test or consult your doctor beforehand.
Rules of preparation for individual blood tests:
Uric acid
Adhere to a purine-free diet - do not eat meat, fish, eggs, cheese, liver, and do not drink red wine 3 days before the test.
Iron
Do not take iron supplements 7 days before the test.
Magnesium
Do not take magnesium-containing medications 7 days before your test.
Phosphorus
Do not take phosphorus-containing medications 7 days prior to testing.
Prenatal screening
Only effective during the first and second trimester of pregnancy. A "Prenatal Screening Questionnaire" filled out by an obstetrician-gynecologist with fetal ultrasound results is required. Duration of ultrasound for the first trimester - no more than 3 days.
Sex hormones in women: FSH, LH, estradiol, prolactin, testosterone, progesterone, antimüllerian hormone
FSH, LH, estradiol, prolactin, testosterone - tests are taken on days 3-7 of the menstrual cycle. Progesterone - on day 21 of the menstrual cycle, unless otherwise specified by the attending physician.
Antimüllerian hormone can be taken at any phase of the menstrual cycle.
Thyroid hormones: TG, TTG, T3, T4
Thyroid hormone medications - do not take 24 hours before taking the tests.
Iodine-containing foods and medications - seafood, walnuts, iodized salt, etc. - Do not take 3 days before the test.
Coagulogram: PV, TV, ACTH, INR, fibrinogen
Anticoagulants (heparin, warfarin, etc.) and antiaggregants (aspirin, thromboass) - not to be taken 2-3 days prior to testing, unless otherwise indicated by the attending physician.
Glucose
Before taking this test, you cannot eat and drink even water, brush your teeth and chew gum. It is recommended to eat only low-carbohydrate foods 3 days before the test.
Glucose tolerance test
First, a standard venous blood collection for glucose testing is carried out, observing the rules of preparation for glucose testing. After that, it is necessary to drink 75 grams of dry glucose diluted in 200 ml of drinking water and take a blood glucose test again after 2 hours, unless other requirements are specified by the attending physician.
PSA (total and free), free PSA index, prostate health index
Prostate massage, finger rectal examination of the prostate, transrectal ultrasound, biopsy, laser therapy, ergometry, cysto- and colonoscopy and any other mechanical impact on the prostate gland - take the analysis before, or 7 days after their performance.
Methanephrine and normetanephrine
Vitamin B, bananas, coffee, monoamine oxidase inhibitors (moclobemide, selegiline, isocarboxazid, etc.), catechol-O-methyltransferase inhibitors, hypotensive medications (α-methyldopa, magnesium sulfate, ormidol, etc.) - do not take 3 days prior to testing unless otherwise directed by the treating physician.
Renin
Will need to be standing or lying down for 1-2 hours before the test, depending on your doctor's instructions.
Drug Monitoring
Determination of drug levels in the blood is done on the recommendation of the attending physician or self-referral in two ways: On an empty stomach, following the general rules of preparation. 1-2 hours after taking the medication.