A normal blood test tells you less than most people think. It tells you that nothing looks badly wrong compared with a broad population. It doesn't tell you how well your body is working, or where it's heading.
I've had my own blood values done since around 2010. Being in the normal range roughly means you look like most other people, and in developed countries a lot of those people are overweight and tired most of the time. I don't find that a very reassuring comparison.
This isn't about bad doctors
I have a deep respect for traditional medicine. Your doctor checks things like your blood pressure and cholesterol to catch people at the dangerous end before there's a crisis. That's an important job. Doctors are trained to cure disease, and they don't have the time to go through your sleep data. I understand why some of them get irritated when someone walks in with their own blood values and DNA results asking for help.
The system asks whether anything is wrong. I ask how good it can get. Those are different questions, and it isn't fair to expect a ten-minute appointment to answer the second one.
What normal means on a lab form
When a result comes back, it sits next to a reference range, the band of values that counts as normal for the general population. It tells you whether you have a diagnosable problem. You can be within range and still be a long way from where you want to be.
Take vitamin D. Around 50 nmol/L is commonly used as the line below which you're deficient, but some European guidelines put the optimal range higher, at 75 to 125 nmol/L. Observational studies link higher levels with less inflammation and fewer infections, although that kind of study can't prove the vitamin D made the difference.
Or take fasting glucose, which is on most standard panels. It can stay normal for years while your insulin is already rising, and insulin often isn't tested at all.
What my own numbers taught me
When I started experimenting on myself in 2008, there was hardly any way to measure your data at home. I had blood tests and a ketone meter, and it was more about how I felt than what I could measure. The first thing I tracked seriously was my heart rate variability. I was still dealing with anxiety at the time, and I could barely register a score on the device's easiest level.
Years later I did a whole-body check at a clinic in the Netherlands. I wasn't looking for a revelation and I didn't get one. Almost everything came back strong for my age. One marker came back low, my omega-3 index, even though I eat oily fish regularly. For me that one finding was worth the whole test. I changed what I was taking, and without the measurement I'd never have known.
If you ask me which of my habits produced which number, I don't know. Maybe it's the food, the exercise, the sleep or the ice bath. One person can't isolate all of that, and it would take a randomised trial with a lot of people. I can only conclude that for me it's the combination. Your numbers would tell a different story, and they may not look like mine.
Not sick isn't the same as well
Medicine has been very successful at extending lifespan. It hasn't done as well on the years in between. A study across 183 countries puts the gap between how long people live and how long they stay healthy at roughly ten years.
That's why I look at function. Do you wake up rested? Is your energy stable? Can you still do the activities you love? When you're stressed, do you recover fast enough? I don't believe there's a forty-five-year-old sitting there thinking about how they want to behave at ninety. They want to feel good now, and for as long as they can keep it going.
You don't need a laboratory to start. A friend of mine was never into any of this. Then he got a sports watch, and one evening he watched his energy score drop while he drank three glasses of wine. That was his signal to drink less. Nobody had to lecture him.
Three things you can do today
Find your last blood test. Look for fasting glucose, vitamin D and any inflammatory markers, and note what's missing. Note the date too, because this is your reference point.
Ask about the markers that were left out. I'd start with fasting insulin, HbA1c and high-sensitivity CRP. You may have to request them from your GP or use a private testing service.
Watch the direction. One result is a snapshot. Your own values over time tell you much more than a comparison with everybody else.
None of this replaces your doctor. If you have symptoms, or a result is flagged, go through it with them, and don't start treating yourself on the basis of a number. Extra tests can also turn up things that mean very little, so talk any surprises through with someone qualified.
How to build your own baseline, step by step, is in my book, More Good Years. Find out more. For structured education beyond the book, there's the Syntony Institute.
Eduard de Wilde has tracked and tested his own biology since 2008. He founded NoordCode and Livehelfi, co-founded the Syntony Institute, and wrote More Good Years. He isn't a doctor, and he sells some of the products discussed in this field. This article is for information and isn't medical advice.
