We believe that the results of the laboratory analyzes reflect the state of he alth. Is it really so? Diet, alcohol, exercise, medications taken, time of day, and stress all affect the body's biochemistry and can cause test results to be false. How important is it and what do you need to know in order not to unknowingly distort the data collected in the study?
We test ourselves to check the condition of our body, to assess the risk of various diseases. But can we be sure that the analyzes performed are reliable? We talk about this with dr. of pharmaceutical sciences Leszek Borkowski, the director's plenipotentiary for analysis and drug management at the Wolski Hospital in Warsaw.
- Why do we need preventive examinations?
Dr. n. Farm. Leszek Borkowski: Research, which we colloquially call prophylactic, shows the he alth condition very generally. Very generally, because when assessing them, the doctor does not analyze, for example, what medications his patient is taking. When we are he althy, do not get sick and enjoy good condition, such an assessment is sufficient. The situation is different with the results of studies of sick people who constantly take some medications.
- Why must a doctor have a different approach to examining sick people?
L.B .: Because the medications taken and some of their metabolites, i.e. compounds produced by cells, can increase or decrease the level of, for example, protein, cholesterol, triglycerides, uric acid, etc. The choice of the research method is also important. Let me give you an example of Lyme disease spread by infected ticks. Sometimes we do not know that we have been bitten, because the characteristic erythema occurs only in about 30% of people. Blood serology is used to detect IgM and IgG antibodies to Borrelia, but they do not appear in the serum until a few weeks after infection. And if the bacteria do manage to enter the synovial fluid or the central nervous system, their blood levels will drop. Serological testing will be negative, although the disease progresses. There are also other tests for Lyme disease, such as searching for bacterial DNA in urine, blood or in the cerebrospinal fluid. The doctor must choose the most reliable in a given case.
- How do drugs affect laboratory test results?
L.B .: Let's take acetylsalicylic acid - even when taken in low doses, it shortens the prothrombin time, i.e.it can distort the efficiency of the blood clotting system. The popular diuretic-induced furosemide, administered in the case of edema associated with cardiovascular insufficiency, underestimates the results of ALT and AST - factors used to assess the degree of liver damage and diagnose its diseases. The same drug inflates the results of FT3 and FT4 thyroid hormone tests. A drug called ACC, recommended as an aid in expectoration of secretions, lowers the levels of creatinine, HDL, triglycerides and uric acid.
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- So when we take furosemide, the results may suggest a diseased thyroid?
L.B .: The results of most studies fall within certain ranges. There is a minimum, and there is a maximum, and everything in between is considered the norm. If someone's thyroid hormone levels are at a minimum and furosemide overestimates the result, there is no tragedy yet. But when the real result is in the upper limit of the normal range, the drug will raise it even more - then it is easy to conclude that you are suffering from a thyroid problem and should be treated.
- The diet has a great influence on the test results …
L.B .: It is much lower than that of drugs. Of course, if someone goes to the test after a sumptuous dinner sprinkled with alcohol, his cholesterol results, for example, will be bad. But with a normal diet, it doesn't really matter. Diet can affect research results if we eat a lot of tropical foods due to certain spices and foods.
- And cigarettes and alcohol?
L.B .: Blood is living tissue that reacts to various factors. If we drink alcohol in the evening and have a blood test in the morning, the results will be false. Alcohol for 38 hours stimulates the increase in GGTP (gamma-glutamyltransferase) activity, which gives a false result, which means that the liver is not working properly. Even one beer drunk in the evening can change the results of the so-called liver tests, i.e. ALT and AST transaminases. Alcohol also has a negative impact on the determination of total cholesterol and its LDL and HDL fractions. Before the blood test, you should not smoke, because the smoke changes the image of blood oxygen saturation, affects the concentration of hemoglobin and the number of red blood cells.
- Our mental condition is also important …
L.B .: Of course. Strongstress will raise your blood glucose levels. The result will be a false positive. When the adrenaline level rises, it will not be possible to properly assess the carbohydrate metabolism.
- Can I go for tests after exercising in the gym?
L.B .: I advise against. The carbohydrate metabolism is also disturbed by exercise. After exercise, due to the increased consumption of energy substances, the level of glucose and triglycerides drops. When the muscles work, enzymes are released from them, which penetrate the serum and affect its image. For example, a high level of CPK (a protein released into the blood from the muscles) may suggest polymyositis (including myocarditis) or heart ischemia. Increasing AST (alanine aminotransferase) will guide the diagnosis towards liver or cardiovascular diseases. High LDH (lactate dehydrogenesis) activity may suggest viral hepatitis, cancer, muscle damage, anemia, inflammation of the lungs, kidneys, or acute pancreatitis.
- So we need to rest for a while before taking the blood for the test?
L.B .: Yes. It is best for the patient to sit down for several minutes. When we stand for a long time, the fluid in the body is displaced (from the vascular bed to the interstitial space) and the blood is compressed by about 10%. This may increase the levels of protein, cholesterol, calcium, magnesium, hematocrit, red and white blood cells. The values of these parameters, caused by a change in body position, depend on the cardiovascular capacity, but they can be overstated by up to 10-15%.
- So when does research make sense?
L.B .: Always, but the patient should know how to prepare well for them, and the doctor, when analyzing their results, must necessarily take into account all factors that may interfere with the assessment of the results.
ImportantBlood on an empty stomach!The tradition of taking blood for fasting tests dates back to the 19th century. Scientists speculated that food might determine the quality of research results, but could not prove it. We currently know that eating a meal is associated with an increase in blood glucose levels, which is of particular importance in assessing the risk of developing diabetes or glucose intolerance. The concentration of triglycerides also increases after a meal. You can have higher OB. The number of white blood cells also changes. Coffee drunk before the test may increase cortisol levels, and this may result in a change in glucose levels.
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