General practitioner Shota Kalandiya of the SM-Clinic medical group has stated that strict fasting before every blood test is a widespread medical misconception.
Speaking to Russian news outlet RT, Kalandiya explained that many routine laboratory investigations do not require patients to abstain from food prior to providing a sample, provided the individual laboratory has not issued specific conflicting instructions for a particular test.
Serological tests designed to detect viral pathogens, including screenings for HIV, viral hepatitis, and syphilis, are among the procedures where eating beforehand does not alter diagnostic accuracy. Serological testing examines blood serum for antibodies or antigens produced by the human immune system in response to infections. Standard food consumption has no significant impact on the presence or concentration of these immunological markers in the bloodstream.
Kalandiya noted that prolonged fasting is also unnecessary for a complete blood count, a standard diagnostic evaluation used to measure red blood cells, white blood cells, hemoglobin, and platelets for general health assessments. However, patients preparing for a complete blood count are advised to refrain from heavy or fat-rich meals immediately beforehand. Consuming high-fat foods can temporarily increase lipid particles in the bloodstream, causing blood serum to appear turbid or cloudy, which can temporarily alter baseline measurements and complicate laboratory analysis.
Requirements for biochemistry and hormone panels
Hormonal evaluations can similarly be conducted after eating in specific circumstances, as food intake does not influence all endocrine markers equally. Kalandiya emphasized that patients should consult their attending physician or laboratory technician before testing, as guidelines vary depending on the specific hormone being measured. Endocrine panels measure chemical messengers secreted by glands to regulate vital functions such as metabolism, growth, and stress response.
In contrast, strict fasting remains essential for biochemical blood panels, particularly those evaluating metabolic function and digestive processing. Tests measuring blood glucose levels, cholesterol, triglycerides, and broader lipid profiles require an empty stomach to ensure precise diagnostic readings. Lipid profiles evaluate circulating fats to assess cardiovascular disease risk, while glucose measurements detect metabolic conditions such as diabetes.
For these metabolic and biochemical screens, Kalandiya advised skipping breakfast on the morning of the appointment while cautioning patients against excessive fasting. He recommended capping the period without food at a maximum of 12 hours, noting that extended starvation can induce metabolic changes, altered hydration levels, and physiological stress that distort test results.
Innovations in blood-based treatments
The guidance follows recent developments in Russian medical practice, where clinicians have successfully introduced autologous blood therapies to heal patient wounds. Autologous procedures involve extracting a small volume of a patient's own blood, processing it to isolate healing factors such as platelet-rich plasma, and reintroducing it to damaged tissue to accelerate cellular repair and wound closure without triggering adverse immune reactions.
