Next to every value on a lab report sits a range, the Referenzbereich, sometimes called Normwerte. It describes where the values of most healthy people fall. By convention it covers about 95 percent of a healthy comparison group.
That definition has a calming consequence: around 1 in 20 values from perfectly healthy people falls outside the range by pure statistics. On a report with 18 values, like a großes Blutbild, one small outlier is expected, not alarming.
Three things are worth knowing. First, the range belongs to the laboratory that ran your test. Labs use different machines and methods, so ranges differ slightly, and you should compare your value against the range on your own report, not against a table from the internet. Second, some ranges depend on age and sex, which is why the same value can be fine for one person and flagged for another. Third, values move with everyday life: infections, sport, stress, fluid intake and the time of day all leave traces.
A value outside the range is a reason to look again and to look at the pattern, ideally with a clinician who knows your history. It is not a diagnosis on its own.
This glossary entry is general information, not medical advice, and it is not intended to diagnose, treat or rule out any condition. Discuss your own results with a clinician who knows your history.
