Family doctor's answers and recommendations for blood tests
Family doctor Laura Narkevičienė's answers and recommendations on how to prepare for blood tests and how to accept the results.
Is it true that you should fast before blood tests?
If we talk about not eating before blood tests, it means not to eat or drink (coffee, tea, juice, etc.), in other words, not to consume anything except water before blood tests.
Fasting should be done before some blood tests such as glucose test, lipidogram (cholesterol fraction test), liver enzyme test gammaglutamyltransferase (GGT), some vitamins (e.g. vitamin B12 test) and some mineral tests (e.g. iron test).
It is recommended not to eat for 8-12 hours before the mentioned tests. These recommendations should be followed, as food substances entering the bloodstream can change and distort the results. After a meal, the blood glucose level increases, so the test result will be misleading and will need to be repeated.
What else should not be done before blood tests? Is it true that you should not drink alcohol or take vitamins the night before? How long should you not smoke or drink coffee? Can you drink green tea?
Before blood tests, it is recommended not to smoke for at least 10-12 hours (as this can falsely increase the number of leukocytes in a general blood test), not to chew gum, for 48 hours. before tests, avoid intense physical exertion, exercise (as this can increase blood indicators: ALT, AST, creatine kinase, which are related to muscle damage and inflammation).
It is recommended not to take vitamins and supplements for at least 48 hours before blood tests. Do not drink alcohol for at least 24 hours before blood tests. Do not drink coffee 8-12 hours before blood tests. Before those blood tests, before which it is recommended not to eat, it is also not recommended to drink green tea.
What should be done before blood tests? Take regularly used medicines e.g. Due to the activity of the thyroid gland, due to high blood pressure or pulse, calm down and sit quietly for 10 - 15 minutes. before a blood test.
Can physical activity affect test results (blood, blood pressure)? Let's say if a person did sports in the morning before the test or in the evening, especially when it comes to more intense training, say, strength?
Yes, blood pressure should be measured at rest, 10-15 minutes. sitting quietly. Before measuring blood pressure, you should wait at least 30 minutes after eating, smoking, sports, alcohol, caffeine consumption.
Feeling stressed, anxiety also affects our blood pressure, so it is normal that if we are worried, stressed, it will be higher than usual. Blood pressure results are also affected by physical activity, depending on our physical preparation, it is normal for systolic blood pressure to increase up to 150 - 160 mmHg during physical activity (especially strength exercises). Thanks to physical exercises, we train our heart, improve our health, after some time the pressure returns to normal.
Of course, if we have any health complaints, increased pressure at rest, we should consult a doctor and carry out the necessary tests. It is best to measure blood pressure in the morning after waking up, before taking medicine, and in the evening.
Blood tests show many indicators. Which are the most important and what do they mean?
The most important blood indicators are: general blood test - usually we do not evaluate only individual values, we also look at the whole, but the most important indicators in the general blood are: Leukocytes - to evaluate chronic or acute inflammation, immunity; erythrocytes - evaluated for anemia; hemoglobin - to evaluate for anemia; platelets - due to blood clotting, liver diseases.
Biochemical blood tests: Glucose - evaluated for glucose metabolism disorders.
TTH - to assess thyroid function.
Creatinine - to assess kidney function.
ALT, AST - to assess liver function, ductus pra
SF - to assess liver and kidney function and disorders, can indicate bile flow disorders and inflammation, stone disease, liver cirrhosis, as well as processes occurring in the bones.
GGT - indicates liver disease and bile flow disorders.
Electrolytes: potassium, sodium, magnesium, ionized calcium, chlorine, iron
Lipidogram - a group of tests that help assess the risk of heart disease. The most important are: low-density lipoproteins (LDL) - "bad" cholesterol. High-density lipoproteins (HDL) - "good" cholesterol. Triglycerides ( TG ) - determine the risk of heart disease and atherosclerosis and lipid metabolism.
Ferritin - shows iron reserves in the body.
CRB - shows inflammation.
ENG - shows chronic inflammation, infectious diseases.
Uric acid - to assess kidney function, risk of rheumatic diseases and effectiveness of treatment.
Vitamin D - helps the body absorb calcium and phosphorus, protects bones from thinning, osteoporosis and rickets.
Can cancer be suspected based on the indicators? If so, which ones?
Cancer markers are protein substances produced by cancer cells. Blood tests are done to check for cancer markers
. These markers can be increased not only in oncological diseases, but also due to other diseases and conditions. Small amounts of various cancer markers can also be found in a healthy person. Also, the amount of cancer markers in patients with oncological diseases may be within the normal range. Thus, these indicators are not specific, oncological diseases can only be suspected, but more detailed tests are required for an accurate diagnosis. Cancer markers are usually performed to assess the patient's condition during treatment with an oncological disease or to evaluate the recurrence and progression of the disease.
If the patient feels healthy, but some cancer markers show elevated values (depending on which organ markers are elevated), a more detailed examination and specialist consultations are recommended, sometimes an early-stage oncological disease can be diagnosed. In Lithuania, according to the preventive program, a blood PSA test is performed every 2 years for all men aged 50-75 (and men from the age of 45, if their parents or brothers had prostate cancer). If an elevated PSA level is detected, the patient is referred for further investigation for suspected prostate cancer. This is to detect early stage cancer.
Another example is the ovarian cancer marker CA125 - research has shown that this marker is predictive of ovarian cancer, but its usefulness is limited by its low specificity. Various benign gynecological and other diseases can also increase this indicator. Studies show that CA 125 is elevated by 1 percent. in healthy women, fluctuates during the menstrual cycle, increases with age, and is also affected by smoking.
Carcinoembryonic antigen (CEA) - most often studied in the monitoring of tumors of the stomach, intestine, breast, lung, pancreas, head and neck.
Breast cancer marker (Ca15-3) - is studied in breast cancer patients during treatment and for possible recurrence of the disease. Here are just a few of the cancer markers, but there are more.
Maybe you can briefly discuss the main indicators - what do they mean, what should they be? What to do if worse? For example If there is a lack of vitamin D, should we start drinking these vitamins?
The norms of blood test indicators are different in each laboratory. If the results of the performed tests do not meet the norms, you should consult a doctor for consultation, assessment and further recommendations. If, let's say, a vitamin D deficiency is detected, the doctor, after evaluating the test, prescribes an appropriate dose of vitamin D, and prescription vitamin D is sometimes prescribed if there are indications.
Vitamin D is important because it affects our mood, energy levels, helps maintain normal muscle function, is less likely to get various infections and reduces inflammatory processes in our body (reduces the risk of autoimmune diseases, the risk of type 2 diabetes, the risk of heart disease). It has been established that a lower concentration of vitamin D leads to increased anxiety, sadness, depression and generally worse psychological and physical well-being.
Vitamin D is naturally produced in the skin when exposed to sunlight. The production of vitamin D in the skin decreases with age, and people with darker skin need more sunlight to produce enough vitamin D. Another source of vitamin D is food. Vitamin D is found in fatty fish, cod liver oil, egg yolk, cow's milk, oranges.
Is it common for people to have perfect blood counts? What are the most common problems shown by blood tests?
People with perfect blood parameters are rare. The most common blood changes are: increased levels of "bad" cholesterol and triglycerides, decreased levels of good cholesterol (HDL), decreased levels of ferritin.
Very often, patients are diagnosed with low levels of vitamin D.
