Recommended quality control for antenatal screening for sickle cell and thalassaemia
Updated 10 October 2024
Applies to England
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This publication is available at https://www.gov.uk/government/publications/sct-screening-handbook-for-antenatal-laboratories/recommended-quality-control-for-antenatal-screening-for-sickle-cell-and-thalassaemia
Due to the limited number of providers of quality control material for haemoglobinopathy testing, the same source material may be marketed by several different suppliers. This means proprietary and apparent third party controls may be identical.
If required, in-house quality control material to aid haemoglobin variant identification must be prepared:
- from confirmed cases or, as a minimum, with identical characteristics in the chosen technique
- in proportions that replicate testing of adults
Screening uses a multi-step process to characterise haemoglobin variants. It is not possible to have controls for all haemoglobin variants. However, laboratories should have controls detailed below within the multistage process.
Recommended quality control measures for this work are as follows:
High-performance liquid chromatography and capillary electrophoresis
The manufacturer should provide calibration and quality control material. This must be analysed as per the manufacturer’s recommendations. This control material is sufficient for HbA2 and HbF measurement. Haemoglobin variants detected by these techniques must have second line testing with appropriate quality control material.
Alkaline and acid electrophoresis
HbF, HbA, HbS and HbC positional controls are sufficient for routine alkaline and acid electrophoresis. It is possible to obtain a commercial FASC control.
Isoelectric focusing
This procedure requires positional quality control material. It is possible to obtain a commercial FASC control. Additional in-house material containing HbDPunjab and HbE is required. Ideally 2 separate mixtures the first containing HbA, HbS and HbDPunjab and the second HbA, HbC and HbE should be prepared. This ensures that the critical separation of the haemoglobins in each mixture occurs satisfactorily.
Mass spectrometry
In house quality control material must be prepared for this technique.