Your blood values are numbers that show what is happening in your blood at that moment: how much iron, sugar, cholesterol or white blood cells it contains. So a result is a snapshot, not a report card. In our experience, people mostly get startled by that one red arrow, while a single off value often says less than the whole pattern. The reference range next to it is a statistical range of healthy people, and it does not apply to everyone in the same way (Ozarda 2016).
This overview explains what blood values are, how to read high, low and normal, and which values often sit in which check. Think of it as the hub: for specific values and symptoms I point you to separate articles below.
What are blood values?
A blood value is the measured amount of a substance in your blood. Think of hemoglobin carrying oxygen, glucose as blood sugar, or CRP as a sign of inflammation. Together they give a view of how a number of processes are running at that moment.
The word value sounds exact, but biology does not work that way. Your blood changes constantly, with what you eat, how you sleep and even the time of day. So a result is a photo, not a film.
Why is there a reference range next to your result?
Next to almost every result sits a reference range, the band that most healthy people fall into, usually the middle of about 95 percent of a healthy group. Falling outside does not automatically mean unhealthy. That range is an average, not a personal limit, and it depends on your sex, age and even the lab that measures it (Sikaris 2014). Read more in the article on reference ranges.
High, low or normal: what does it mean?
Most people mainly want to know: is this bad? In short, it depends on how far your value is off, whether the pattern fits your symptoms, and whether it stays that way on repeat. This table gives a rough guide.
| Result | What it usually means | What is often sensible |
|---|---|---|
| Within the reference range | Your value sits in the range of most healthy people | Usually no action, a useful starting point |
| Just outside the range | A mild deviation that can fluctuate | Often repeated and read in context |
| Clearly raised or lowered | A bigger difference from the range | Discuss with your GP, sometimes further testing |
If a value is just outside range, do not panic. If it is off more clearly, or several values fit your symptoms, that is more reason to look further. What suits your situation, you decide with your GP. Read more at an abnormal blood value.
Which values sit in which check?
Not every blood test measures the same thing. This table lists common values with what they measure and where they often belong.
| Value | What it measures | Often part of |
|---|---|---|
| Hemoglobin (Hb) | Oxygen transport in your blood | Complete blood count |
| Ferritin | Your iron store | Anaemia and fatigue work-up |
| Glucose | Your blood sugar at the moment of the draw | Basic health checkup |
| CRP | A pointer to inflammation | Inflammation work-up |
| eGFR and creatinine | How well your kidneys filter | Kidney function work-up |
| TSH | The signal that steers your thyroid | Thyroid work-up |
The most common part is the complete blood count, which measures your red and white blood cells and platelets in one go. I cover that separately.
To measure a number of values without a referral, you can choose a basic health checkup or an extended health checkup at Vitalcheck. They give a broader view of a number of values, not a verdict on your health. Which values sit in a standard panel is covered at what is in a standard blood test.
From result to next step
A result is only useful once you know what to do with it. Often a value points you to a specific theme. Here are the most used routes from this hub.
- Mostly tired? See always tired.
- Thinking of your thyroid? Read thyroid symptoms and values.
- Suspect a deficiency? See vitamin deficiency.
- Pale or drained? See iron deficiency and anaemia.
- Questions about your kidneys? Read kidney function, creatinine and eGFR.
- A raised inflammation value? See inflammation markers.
What affects your blood values?
Before you draw conclusions, it helps to know that many things can colour your result. The time of the draw, whether you fasted, how much you moved the day before, and even stress. Some supplements, like biotin, can disturb certain measurements. For some values fasting is still common, while for others it is no longer needed (Nordestgaard 2016). Read more at fasting before a blood test.
What do you do about an abnormal value?
An abnormal value is not a diagnosis, but a signal. The next step is almost always a conversation with your GP, who combines your result with your symptoms. Keep your symptoms for a few weeks and save your result, so you can compare values later and see a trend. Do not change medication or supplements based on a single result. Discuss an abnormal value with your GP first.
Frequently asked questions about blood values
Is a value outside the range always worrying?
No. Because the reference range is a statistical average, part of healthy people fall just outside it by definition. A mild deviation is often repeated and read in context before anything is attached to it.
Why do reference ranges differ per lab?
Each lab uses its own equipment and methods, and sets its own ranges. So the same result can fall just inside at one lab and just outside at another. Compare values within the same lab where you can.
Can I measure my blood values without a referral?
Yes. At Vitalcheck you can test a number of values without a referral, and every result is reviewed by a BIG-registered doctor. That gives context, not a diagnosis. For treatment decisions you stay with your GP.
References
- Ozarda Y. Reference intervals: current status, recent developments and future considerations. Biochem Med (Zagreb). 2016. PMID: 26981015.
- Sikaris KA. Physiology and its importance for reference intervals. Clin Biochem Rev. 2014. PMID: 24659833.
- Nordestgaard BG, et al. Fasting is not routinely required for determination of a lipid profile. Eur Heart J. 2016. PMID: 27122601.
- Thuisarts.nl. About blood testing.
Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
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