A simple guide to blood tests — no medical degree required
A simple guide to blood tests — no medical degree required
OM-Digital team
Moscow, 2026
Chapter 1. A familiar situation: a sheet full of numbers and no explanation
Chapter 2. What an ordinary blood test actually consists of
Chapter 3. Five indicators that scare people most often — needlessly
Chapter 4. When a deviation is a genuine reason for concern
Chapter 5. How AI helps you make sense of things faster than an internet search
Chapter 6. How to prepare for a conversation with your doctor, armed with understanding
Conclusion. Numbers are a language, not a verdict
This book was written for one specific minute — the one that comes right after you open your blood test results and see a column of abbreviations and numbers, some of which are highlighted in red for some reason. The doctor handed you the sheet, said "if you have questions, we'll discuss them at your appointment in two weeks", and that was it. Two weeks is a long time if one of the indicators looks frightening and googling is scary, because the internet loves the gloomiest scenario for any query.
There will be no unexplained medical terms here and no attempt to replace your doctor — on the contrary, the book was written precisely so that the conversation with your doctor becomes more meaningful and the two weeks of waiting pass more calmly. What follows are six short chapters, each readable in a single evening — ideally with your own test sheet next to you.
Natalia received her complete blood count results in the clinic's app at ten in the evening — the doctor had already left, reception wasn't answering, and next to "Leukocytes" on the list there was a number with an upward arrow and not a single word of explanation. She opens a search engine, types "elevated leukocytes", and the very first article on the screen begins with the word "oncology" — although in reality elevated leukocytes most often mean a common cold or a recent vaccination.
A familiar story: numbers on their own say nothing without context — which laboratory, what kind of week you had before the test, whether there are any symptoms at all. But when the sheet is opened late in the evening, alone, it isn't always possible to explain this to yourself calmly — and that is a completely normal reaction, not "panicking". So we'll begin precisely with what the most common lines on the sheet actually mean.
Most often a person ends up with one of two kinds of test: a complete (clinical) blood count or a biochemical panel. The complete blood count is like a census of blood cells: how many erythrocytes (they carry oxygen), leukocytes (protection against infection), platelets (clotting), what the haemoglobin level is, and the ESR — erythrocyte sedimentation rate, an old but still-used marker of inflammation in the body.
The biochemical panel looks at something else — how the internal organs are working, through the chemical composition of the blood: glucose (sugar), cholesterol, liver function indicators (ALT, AST) and kidney function (creatinine, urea). For a beginner the key idea is simple: no test is read in isolation from the others or from how the person feels overall — a doctor always looks at the whole picture, not at a single line with a deviation.
Leukocytes slightly above normal are almost always a reaction to a recent cold, stress, or even a heavy meal before the blood draw, not a sign of something serious. ESR slightly elevated is an extremely non-specific indicator — it reacts to anything from a mild cold to plain lack of sleep, and on its own almost never points to a specific diagnosis.
Cholesterol at the upper limit of normal in a person with no other risk factors is a topic for a calm conversation with the doctor at the next routine visit, not a reason to panic that same evening. Haemoglobin slightly below normal in a woman is a common story, especially on certain days of the cycle, and on its own is almost never a cause for alarm. And a single small deviation in glucose is often simply the result of the test not being taken strictly on an empty stomach, as the method requires.
The general principle worth remembering most firmly: one small deviation in one indicator on a sheet of twenty lines is a statistically almost inevitable thing, not an alarm signal. Moreover, the "normal" ranges differ slightly between laboratories, which is why every sheet shows the normal range of that specific laboratory next to the result — that is what you should compare against, not a number found on the internet.
To be fair: there are situations when you shouldn't postpone the visit until the routine appointment. A significant deviation (not 5%, but several times over) in several related indicators at once is a different story from a single number slightly past the edge of normal. The same applies when a deviation in the tests is accompanied by real symptoms — persistent weakness, unexplained weight loss, a prolonged fever.
In such a situation the right step is not to sit with it until the routine appointment in two weeks, but to contact the doctor sooner, describing precisely the combination of "what the tests show + what I feel at the same time". Doctors appreciate patients who come not with a printout of an internet article, but with a clear description: what is bothering them, for how long, and what the test showed.
Returning to Natalia's story from the first chapter: instead of a late evening with frightening articles, she could have photographed the test sheet on her phone and received a calm explanation of every line — what the indicator means, what its normal range is in this particular laboratory, and whether it is worth worrying about at all. The difference from an ordinary search is fundamental: a search returns a list of links to every possible cause of the deviation, from the most harmless to the most frightening, while an analysis of the whole sheet, taking into account how the indicators relate to one another, gives a far calmer and more balanced picture.
It is exactly for this task that we at OM-Digital are building the Doctor AI app — you upload a photo or PDF of the test sheet, describe anything that worries you, and get a clear breakdown without medical jargon and without the scariest diagnosis from the first line of a search. It is not a replacement for a doctor and not a diagnosis — but a calm way to prepare for the conversation with one, instead of spending the evening anxiously on forums. The project page with screenshots is here.
Once you understand what the lines on the sheet mean, the conversation with the doctor changes qualitatively: instead of "what does this mean?" you can ask to the point right away — "I see my leukocytes are slightly elevated, I had a cold a week ago, could that be related?". The doctor spends less time explaining the basics and more on what really matters in your specific case.
A good approach before the appointment is to write down, on a sheet of paper or in your phone's notes, the two or three indicators that genuinely worry you and one or two sentences about how you feel. This saves appointment time and reduces the risk that an important question is forgotten in the consulting room out of nervousness — many patients remember "I meant to ask about..." only once they are back in the corridor.
A blood test is simply another way the body reports on itself, no different in principle from temperature or pulse. Learning its basic "vocabulary" is not a medical speciality but a sensible everyday skill, like being able to read the ingredients on a food label. The goal of this book was not for you to start diagnosing yourself from a sheet, but for the evening after receiving your results to pass more calmly and the conversation with your doctor to be more focused.
👉 Want to make sense of your test sheet right now, without waiting for an appointment? Try the app Doctor AI
Don't wait for an appointment to understand what is happening — describe your symptoms or upload a test.
See the Doctor AI appThe cost of a blood biochemistry panel at a laboratory rarely explains why there are so many indicators and which ones are looked at first. The book goes through the sheet line by line — what each number means and which deviations genuinely require a doctor's attention.