Synopsis
Select and interpret haemoglobin analysis in context, recognise assay and transfusion limitations, confirm consequential variants molecularly, and translate paired results into non-directive reproductive counselling.
- Modern laboratories use high-performance liquid chromatography, capillary electrophoresis, isoelectric focusing or complementary methods; the report must be interpreted with method, age and clinical question.
- Adult haemoglobin A predominates normally, with small HbA2 and HbF fractions; newborns predominantly express HbF, so infant patterns use different algorithms.
- Raised HbA2 supports beta-thalassaemia trait, but iron deficiency, transfusion, delta-chain variants and coexisting haemoglobin variants can alter the result.
- Alpha-thalassaemia trait often has normal adult fractions and cannot be excluded by a normal electrophoresis or HPLC report.
- Recent transfusion introduces donor haemoglobins and can dilute or create peaks; document the date, number of units and pre-transfusion sample availability.
- Sickle solubility tests cannot distinguish trait from disease, are unreliable in newborns or after transfusion, and should not replace quantitative fractionation.
- Some variants co-elute or migrate together, so the laboratory may need a second analytical platform and targeted molecular confirmation before counselling.
- Interpret fractions alongside full count, MCV, MCH, ferritin, haemolysis, family history and ethnicity as one clue rather than a biological diagnosis by ancestry.
- Carrier counselling explains that the carrier is usually healthy, avoids unnecessary restrictions and tests the reproductive partner before calculating fetal risk.
- At-risk couples should receive genotype-specific, non-directive discussion of prenatal diagnosis, preimplantation testing and pregnancy or newborn pathways through the national screening programme.
Key red flags
A pregnant carrier whose partner is untested needs prompt screening coordination so fetal-risk assessment and options are not delayed.
Investigation priorities
Provide globin-production context for the fraction pattern.
Management branches
Microcytosis, haemolysis, family history, pregnancy or newborn screening raises haemoglobinopathy.
- Provide age, pregnancy, transfusion date, hydroxycarbamide exposure, full count and iron status to the accredited laboratory.
- Use quantitative haemoglobin separation rather than a solubility screen for carrier or disease classification and retain any pre-transfusion sample.
- Request complementary analysis or molecular testing when alpha trait, co-elution, compound heterozygosity or reproductive risk cannot be resolved by the initial platform.