Do I need to donate blood for analysis

We are used to searching online for ANSWERS TO MOST OF THE QUESTIONS OF EXCITING US . In this series of articles, we ask just such questions – burning, unexpected or common – to professionals in a variety of fields.

When information on any diseases and conditions is available on the Internet, many medicines are sold without a prescription, and paid examinations can be done at least every day, it is easy to go too far in health care. Does it make sense to donate blood for analysis yourself from time to time? What and when to check so as not to miss something serious? Does any abnormality on the printout mean you are sick? We asked these questions to an expert.

Galina Palkova

doctor-dermatologist, endocrinologist ‘ Clinic Julia Scherbatova 

For many, this will be a surprise, but in the absence of specific complaints and hereditary predispositions, it is not necessary to do tests at all. There is no standard set of “recommended annual tests”; you do not need to donate blood even for a common cold or before a routine vaccination. And it makes no sense to assign yourself any research at your own discretion: to take care of your health, an annual conversation with a competent doctor who has been leading you for a long time is more than enough.

At the same time, it is important to understand that the absence of complaints is a loose concept. Frequent headaches, bruising under the eyes, loss of energy, depression, weight gain, sudden love for sweets, irritability, hair or skin problems are what you need to go to the doctor with. It is dangerous to explain such symptoms for a long time by saying that you simply did not get enough sleep. True, trying to find the cause on your own, checking suspected diagnoses from the Internet with the results of tests from the laboratory near the house, is even more dangerous.

In what cases are tests still needed? In the life of most people, there are three stages at which it is recommended to undergo a detailed screening. The first one is at the age of eighteen or twenty, when it is important to make sure that the body has entered the reproductive period and is working correctly. At this stage, hereditary problems and early stages of disorders can be identified, which can develop into serious chronic diseases if they are not dealt with.

The second important stage is the moment when the level of sex hormones begins to decrease (35–40 years old). Menopause or andropause at this time does not yet occur, but the level of hormones begins to decrease markedly, and global changes occur in the body: the condition of the skin worsens, the lack of oxygen in the tissues increases, against the background of a decrease in the production of sex hormones, weight gain may begin. Being mindful of yourself at this point can make it easier to enter menopause in the future.

The third stage is not tied to a specific age – this is preparing for pregnancy and the pregnancy itself or planning for conception, if you are a man. Quitting smoking and drinking alcohol at this point is important, but not enough. In order to guarantee good health for yourself and your child, it is important to undergo a detailed examination and, if necessary, correction.

At all these stages, it is necessary to do general clinical and biochemical blood tests, blood tests for hormones and basic trace elements (vitamin D and B12, copper, zinc, magnesium, folic acid), parameters of oxidative stress (hemoglobin and iron), as well as ultrasound of small organs. pelvis, thyroid gland and mammary glands. A general clinical analysis shows the number and ratio between blood cells – erythrocytes, leukocytes, platelets, and biochemical analysis determines the concentration of different molecules, such as glucose or cholesterol. It is important to understand that you cannot go with this list to the nearest laboratory and calm down if the results are within the normal range – just like panic if they fall outside the normal intervals. Analyzes should be prescribed and, most importantly, only a doctor should interpret their results.


In addition, blood and urine tests are by no means the main diagnostic methods. In rare cases, it is possible to make a diagnosis only by the results of a blood test.

There are several reasons for this. For example, the reference values ​​are not absolute: in fact, the norm for a particular patient can vary greatly depending on your gender, age, height, weight, the presence of certain diseases, a list of what you have been ill with before, and even ethnic characteristics. In addition, the normal range may differ slightly between different laboratories: in the printout of the results, your hemoglobin level will be marked with an asterisk as too low, and in the other it will be normal, although close to the lower limit of the normal range. Such differences may be due, for example, to the equipment used. Only a doctor can decide whether the result is normal.

In addition, blood and urine tests are auxiliary, but by no means the main diagnostic methods. It is possible to make a diagnosis only by the results of a blood test in the rarest cases – with rare infections and a couple of endocrine diseases. In other cases, it is important to look at the ratio of different parameters with each other, at their combination with symptoms, history and characteristics of a particular patient. In a word, only a good doctor can do it again.

Like any other high-tech industry, laboratory diagnostics are constantly evolving, and the methods are becoming more complex and accurate. If a general clinical blood test or an analysis for thyroid hormones can be performed anywhere, then more complex things – a blood test for homocysteine, vitamin D, most trace elements, indicators of oxidative stress – are best done in laboratories where there is equipment for mass spectrometry, one of the most advanced techniques. On the other hand, donating blood for the simplest tests in a cool and expensive laboratory is often a waste of money, so it is better to listen to the advice of a doctor who will explain which parameters it is better to go to a more modern laboratory for analysis.

Much also depends on the state in which you are at the time of donating blood – and which can greatly affect the result. For example, on the eve of donating a blood sample for analysis for prolactin, you cannot have sex, and you cannot eat sweets, fatty foods or smoke in front of others. In absolutely all cases, it is better not to drink alcohol. The results may depend on the phase of the menstrual cycle, vitamins taken and a huge number of factors. It also happens the other way around: many of the usual restrictions are outdated from the point of view of modern medicine and a competent doctor will recommend, for example, donating blood not on an empty stomach, but after dinner.

In general, not all conditions are immediately reflected in the test results directly. Some hormonal disorders often first appear as a deficiency or excess of vitamins or trace elements, with the use of which these hormones are synthesized. Or the simplest example: in hypothyroidism – a reduced function of the thyroid gland – the level of its hormones may be normal, and not lowered, so their amount as a result of the analysis will not say anything. In this case, the pituitary hormone, which stimulates the thyroid gland (thyroid-stimulating hormone), will be produced in large quantities in order to spur its function. It is hardly possible to understand all these intricacies without a higher medical education, but it is easy to miss the onset of the disease by independently prescribing tests for yourself.

There has been a lot of talk lately about genetic tests – but they cost a lot of money, and not everyone benefits. For example, for some already identified tumors, analysis for genetic mutations is necessary – for the same breast cancer, it helps to choose an effective treatment and better understand the prognosis. But for prevention, not everyone needs to do genetic tests; even if such a test is needed, then we are talking about the profiles of specific genes, and not a complete decoding. It turns out that only a professional is capable of prescribing and interpreting the test results. And the patient’s task is to find an attentive doctor who can be trusted.

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