Hb Electrophoresis (Thalassaemia Test)
Also known as: Haemoglobin electrophoresis, Thalassaemia test, HPLC for haemoglobin, thalassemia ka test, shadi se pehle thalassemia test
Separates and measures the types of haemoglobin in your blood (HbA, HbA2, HbF and abnormal types such as HbS). It is the main test for beta-thalassaemia trait.
Why it's ordered
Checking for thalassaemia trait or sickle cell, especially when red cells are small (low MCV) but iron is normal, and for carrier screening before marriage or pregnancy.
Preparation
No fasting needed. Tell the lab if you have had a blood transfusion in the last 3 months.
Typical adult values
| HbA | about 95–98% |
|---|---|
| HbA2 | about 2.0–3.3% |
| HbF | below about 1% |
Ranges vary between labs and methods. Always use the range printed on your report.
If it's high
HbA2 above about 3.5% suggests beta-thalassaemia trait (minor). Raised HbF can occur in thalassaemia and some other conditions. An abnormal band such as HbS or HbE shows a haemoglobin variant.
If it's low
A low or borderline HbA2 can occur in iron deficiency, which can hide beta-thalassaemia trait.
Good to know
Thalassaemia trait is common in Pakistan. If both partners carry beta-thalassaemia trait, each pregnancy has a 1 in 4 chance of thalassaemia major, so carrier testing before marriage is worth considering. This test does not reliably detect alpha-thalassaemia trait, which needs DNA testing. Iron deficiency should be corrected first, as it can mask the result.
Common questions
Which test shows thalassaemia trait?
Hb electrophoresis (or HPLC). HbA2 above about 3.5% suggests beta-thalassaemia trait. Alpha-thalassaemia trait needs DNA testing.
Should we test for thalassaemia before marriage?
It is worth considering. If both partners carry beta-thalassaemia trait, each pregnancy has a 1 in 4 chance of thalassaemia major.
Can iron deficiency affect the result?
Yes. Iron deficiency can lower HbA2 and hide beta-thalassaemia trait, so it should be corrected first.
What is a normal HbA2?
Typically about 2.0–3.3%. Always use the range printed on your report.