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Diagnosing α-thalassaemia requires second line diagnostics involving DNA analysis. Multiplex ligation probe amplification® (MLPA®) is a molecular technique introduced as a diagnostic tool for α-thalassaemia. This semi-quantitative technique determines the relative copy number of up to 60 DNA sequences and is able to detect deletions and duplications in a DNA sample. A novel commercial tool, the α-Globin StripAssay®, aims to detect the most common α-thalassaemia deletions and point mutations. The test involves three steps: DNA isolation, PCR reaction and a hybridization step to test strip containing allele-specific oligonucleotide probes immobilised as an array of parallel lines.

Our objective was to evaluate the α-Globin StripAssay® as a useful alternative for MLPA® in second line α-thalassaemia diagnostics.

Eight samples, including 7 known deletions (_ _SEA, _ _THAI, _ _MED, homozygous and heterozygous - α^3.7, heterozygous - α^4.2, (α)^20.5) and 1 mutation (Hb Constant Spring) were analysed using multiplex Gap-PCR (deletions) and Sanger sequencing (point mutation) at the Leiden University Medical Center. These samples were anonymised and analysed in duplicate by MLPA® and α-Globin StripAssay® at our center. A comparison of diagnostic performance, interpretation, turnaround time (TAT) and costs (reagent and labour) was done.

There are no significant differences between the MLPA® and the α-Globin StripAssay® results and each identification corresponded to the result of the reference lab in Leiden. MLPA® however provided additional information about underlying polymorphisms. Interpretation of the α-Globin StripAssay® was easier and faster compared to MLPA®. The α-Globin StripAssay® proved to have a shorter TAT, but on the other hand, the costs for MLPA® were significantly less.

Despite its straightforward interpretation, shorter TAT and the ability of detecting both (known) deletions and point mutations, the significantly higher costs of the α-Globin StripAssay® may hinder it’s routine use. Specialised laboratories are usually acquainted with the MLPA technique and in these settings the ability to detect both known and unknown deletions is a plus for research purposes.