Carrier of beta-thalassaemia

Clinically: Beta-thalassaemia trait · also thalassemia trait, thalassemia minor, thalassaemia minor, beta thalassemia trait, thalassemia carrier

genetic MONDO MONDO:0044210 unverified

This describes what this condition typically looks like. It is not a diagnosis and cannot tell you whether you have it -- patterns overlap, results vary between labs, and the same numbers mean different things in different people.

unverified These explanations are written to be easy to read and have not yet been checked against a source. The ranges and measurement notes on this page show theirs.

definition unverified

A person carries one changed gene for beta-thalassaemia, passed down in families. Their red blood cells are small, and they may have mild anaemia or none at all.

Carrier state for beta-thalassaemia: one variant HBB allele (also called thalassaemia minor). It usually causes microcytosis with no or mild anaemia, and is diagnosed by an HbA2 above 3.5%.

caveats unverified

Most carriers have no symptoms and find out from a routine blood count. The small red cells look a lot like iron deficiency, so the two must be told apart. Iron does not fix the anaemia of thalassaemia trait.

No clinical version written yet.

The typical lab pattern

Consistent with it

Fits the picture, but not enough on its own.

Mean corpuscular volume	low	—	Small red cells (MCV below 80 fL) are usually how a carrier is first found, often by chance on a routine blood count.
Mean corpuscular hemoglobin	low	—	Low MCH with low MCV is used as a screening flag: a guideline used in Indonesia sends people with MCV below 80 fL and MCH below 27 pg for further tests.
Erythrocyte count	high	—	The red cell count tends to be high for how small the cells are. A high count with a low MCV points towards beta-thalassaemia trait rather than iron deficiency.
Hemoglobin	low	—	Haemoglobin may be mildly low, or normal. Iron treatment does not raise it.
Ferritin	either	—	Checked to tell the trait apart from iron deficiency, which also gives small red cells. Ferritin is usually normal in the trait; a low ferritin points to iron deficiency, which can also be present at the same time.