An abnormal blood value: what does it mean and what now?

An abnormal blood value often feels alarming, but it is a signal, not a diagnosis. About 1 in 20 results falls just outside the reference range statistically, even in healthy people (Sikaris 2014). In our experience people get startled by that red arrow, while the key question is not whether a value is off, but by how much, and whether it stays that way on repeat.

This article belongs to the overview about your blood values and focuses on that one value that stands out.

What does an abnormal value mean?

A value outside the range means you fall outside the middle band of healthy people at that moment. That can be an innocent fluctuation, a temporary effect of your lifestyle, or the start of something that deserves attention. The number alone does not tell you which. So a doctor looks at the whole: how far off, do your symptoms fit, and are several values off together?

How bad is it? A rough guide

A mildly raised CRP without symptoms can be a short-lived inflammation that settles. A low ferritin with tiredness and pallor is more of a pattern worth looking into.

Why does a doctor often repeat the measurement?

Blood values fluctuate. Today's measurement can be slightly different from next week's, due to food, sleep, exercise or timing. So doctors often repeat a mildly abnormal value before drawing conclusions. A second measurement filters out flukes. If the value stays off on repeat, that is a firmer signal than one result.

What can you do yourself?

The most useful thing you can do is save your result and track your symptoms for a few weeks, so you can compare values later and see a trend. To have a deviation checked, you can do a basic health checkup at Vitalcheck, reviewed by a BIG-registered doctor. If your deviation fits a symptom, theme pages help further, for example on kidney function or inflammation markers. Do not change medication based on a single result.

Frequently asked questions about an abnormal blood value

Should I worry about one abnormal value?

Usually not right away. One mildly off value without symptoms is often repeated and read in context. If a value is clearly off or fits your symptoms, discuss it with your GP.

Can stress or exercise affect my values?

Yes. Intense exertion, stress, lack of sleep and your last meal can temporarily shift certain values. So a repeat at a calm moment often gives a fairer picture.

What if several values are off at once?

There may be a shared cause, or it may be chance. A doctor looks at the pattern to decide whether further testing is useful. See also the overview about your blood values.

References

• Sikaris KA. Physiology and its importance for reference intervals. Clin Biochem Rev. 2014. PMID: 24659833.
• Ozarda Y. Reference intervals: current status, recent developments and future considerations. Biochem Med (Zagreb). 2016. PMID: 26981015.
• 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.