Dr. Dmitry Denisov, director of the medical analysis laboratory, pointed out that some patients’ neglect of the instructions regarding preparation for blood draws may lead to difficulty or complication in interpreting laboratory test results.
The doctor explained that a number of everyday factors such as smoking, stress, physical activity and food intake can directly affect the results of laboratory tests.
He stated that there are three common, but often overlooked, ways that can distort test results, the most prominent being smoking. He explained that nicotine triggers a series of stress-related responses in the body. The adrenal glands release the hormones cortisol and adrenaline, while the liver releases glucose from its stores. This can lead to a temporary increase in blood sugar levels, even in healthy individuals, appearing as a rise in fasting blood sugar. He added that chronic smokers may exhibit elevated red blood cell indices as a compensatory mechanism for oxygen deficiency in the tissues, which can mask genuine disturbances in oxygen metabolism.
He pointed out that stress or physical activity before the analysis can also affect the results, explaining that simple activities such as climbing stairs, brisk walking, or anxiety before the examination lead to the release of stress hormones, such as cortisol, prolactin, and adrenaline, which may be reflected in other indicators in the analysis in a way that mimics hormonal or metabolic disorders.
Denisov emphasized that the rules for preparing for laboratory tests are not merely procedural formalities, but are based on clear biochemical principles. He stated, "Every item in the instructions, such as abstaining from smoking for an hour or fasting for 8 to 12 hours, has a direct scientific basis. Patients often do not disregard these instructions intentionally, but rather due to negligence or a lack of knowledge. However, adhering to them ensures accurate results that reflect the true state of health, which helps the doctor make the correct diagnosis and spares the patient the need for repeat tests or doubts about their accuracy."
