Information
The purpose of the haemoglobinopathy screen is to detect, identify, and quantify abnormal haemoglobin variants and thalassaemic carriers. This examination is essential for the diagnosis and classification of inherited haemoglobin disorders, which may present with microcytosis, unexplained anaemia, or a family history of haemoglobinopathy. The procedure also supports appropriate clinical management, genetic counselling, and further investigation where required.
Sample requirements
- Whole blood collected into 1 vacutainer containing EDTA (purple top)
- A full blood count (FBC) and ferritin is also required for interpretation
- Please indicate the patient’s ethnicity/country of origin in the clinical details
- If test is part of the Sickle Cell and Thalassaemia screening programme, all samples must be accompanied with a family origin questionnaire
Minimum volume
- Adult: 2ml
- Paediatric : 1ml
Reference range
There are no absolute reference ranges for this test, as interpretation is based on qualitative and quantitative haemoglobin fractions and red cell indices. However, normal adult haemoglobin typically includes:
| Units | Male | Female |
|---|---|---|
| Hb A % | 96% – 98% | 96% – 98% |
| Hb A2 % | 1.5 – 3.5 | 1.5 – 3.5 |
| Hb F % | <1 | <1 |
Limitations
Due to the diversity of Haemoglobin variants and thalassaemia syndromes there will always be some situations that require further tests, or family studies before a useful clinical diagnosis can be achieved.
If an individual has had a blood transfusion and any of the transfused red cells are still present, misleading data and conclusions may result. In this situation, repeat testing should occur at least 4 months after the transfusion.
Other clinical situations that may prevent accurate interpretation of the results are HIV, severe iron deficiency anaemia (including a Hb level of <80g/L), liver disease, and B12/folate deficiency.
Where a patient has had a bone marrow transplant (BMT) or gene therapy it is likely that the results obtained will reflect the BMT donor / post gene therapy status and will not accurately represent the genetic status of the patient.
It may not be possible to provide accurate results on short, clotted or haemolysed samples. These will be rejected with an appropriate comment.
Samples must not be exposed to extreme temperature e.g. next to heat source, left in direct sunlight or frozen.
Analysing laboratory
Haematology Lab, James Cook University Hospital, Marton Road, TS4 3BW
Advice
For clinical advice please contact Dr Plews on extension 54381 or the on-call haematologist via the switchboard on 01642 850850.
For laboratory advice or in the event of a missing report, please contact the haemoglobinopathy team on 01642 282637, extension 52637 or [email protected].