Histamine (plasma)
Histamine is a substance (a mediator) that mast cells and basophils release during an allergic reaction; it causes flushing, itching, swelling and cramps. In plasma it is very short-lived.
| Rating | Range | What it means |
|---|---|---|
| Good | below 1 µg/L | Plasma histamine within range. |
| Talk to a doctor | 1 µg/L and above | Elevated — possible mast cell/basophil activation; the sample is very sensitive, to be confirmed by a doctor. |
Why it matters
It rises transiently during an acute reaction; for assessing anaphylaxis, tryptase is more reliable.
If it’s low
Low histamine is of no clinical significance.
If it’s high
Elevated plasma histamine may reflect activation of mast cells/basophils (e.g. during a reaction), but the value is often misleading due to sample instability and release from blood cells during the draw.
What to do
Do not interpret individual values on your own — because the sample is unstable, they are often unreliable. If you suspect severe allergic reactions, consult an allergist (tryptase is often more useful). For suspected food-related histamine intolerance, see the DAO marker.
Read together with
Tryptase (baseline) · DAO
This content is for information only and is not a substitute for medical advice. Talk to your doctor about your results.
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