Blog
Preparing for blood biochemistry: how to get accurate results the first time
Do you have a blood test coming up? It seems like nothing complicated: you come, you pass, you leave. But in the morning before the procedure, the question arises: "Can I have water?", "Can I have at least a sip of coffee?", "What if I only ate an apple last night - is that normal?" All this matters, especially when it comes to biochemical blood test — one of the most accurate and at the same time most sensitive tests.
The accuracy of biochemistry directly depends on how responsibly you approach the preparation. An improper breakfast or evening fast food can not only "spoil the numbers", but also lead to a false diagnosis or unnecessary examinations. To avoid this, read on.
Why is a biochemical blood test needed?
Biochemistry gives the doctor a detailed picture of the state of internal organs and systems. It allows:
check the work liver (ALT, AST, bilirubin)
evaluate the function kidneys (creatinine, urea)
learn about glucose and lipid levels (cholesterol, triglycerides)
reveal inflammation, dehydration, metabolic disorder
monitor chronic diseases or treatment effectiveness
This analysis is included in most preventive programs and is indispensable in therapeutic, endocrinological, gastroenterological and cardiological practice.
Why preparation is important
A biochemical blood test is a "snapshot" of your metabolism. And, like a camera, it all depends on the lighting conditions, angle, and focus. If you ate a cake in the evening or drank coffee in the morning, your body may still react to it at the time of blood donation. And instead of an accurate result, you will receive altered numbers.
Quote from endocrinologist Oleksandr Vasylenko:
«"Sometimes, drinking a glass of juice or taking vitamins in the morning is enough to mess up a glucose or lipid profile. It seems like a small thing, but every detail is important for diagnosis.".
Basic rules for preparing for biochemistry
Don't eat for at least 8–12 hours before the test. The last meal is a light dinner, no later than 7:00–8:00 p.m.
Water is allowed., but only pure, non-carbonated. No more than 1 glass in the morning.
Alcohol is prohibited. in 24–48 hours. It affects liver function, triglyceride levels, and enzymes.
Physical activity — no. Do not go for the test after a gym or an active run.
Smoking can distort glucose, hormone, and lipid levels — do not smoke 1–2 hours before the procedure.
Coffee, tea, juices, chewing gum are prohibited.. They trigger metabolic processes even before blood is drawn.
If you are taking medication — be sure to tell the doctor. Some medications need to be discontinued the day before, while others require testing before taking them.
Table: What can affect the biochemistry result
| Indicator | Influence of external factors | How to avoid error |
|---|---|---|
| Glucose | Stress, food, lack of sleep | On an empty stomach, calm, good sleep |
| Cholesterol | Fatty food, alcohol | Diet 2 days before the analysis |
| ALT, AST | Alcohol, medications | Abstain from alcohol, coordinate medication intake |
| Bilirubin | Hunger, medications | Do not fast for longer than 14 hours |
| Urea, creatinine | Physical activity | Avoid sports for 1 day |
| Total protein | Plenty of water | Do not drink more than 200 ml in the morning |
Frequently asked questions
Can I drink water before the test?
Yes, but in moderation - no more than 1 glass, without gas and additives, 1–2 hours before delivery.
Can I donate blood if I am taking medication?
It depends on the drug. Some have no effect, others completely change the indicators. Check with your doctor.
When is the best time to take the test?
From 8:00 to 10:00 in the morning - this is when the reference (normal) values of most laboratory indicators are established.
What to do after delivery
After the analysis, it is possible and even advisable to have breakfast - it is better to bring a sandwich or banana with you.
If you feel dizzy or weak, sit in the hallway for a few minutes or contact the staff.
Results are usually ready in 1–2 business days
Do not interpret the results yourself - consult a doctor.
Biochemistry is not just a part of the examination. It is a moment when you can see how the body «works» from the inside. Following simple but important rules before taking the test is not a burden, but part of taking care of yourself and your doctor. The accuracy of the results starts with you.
