Results of a case-detection programme for α 1-antitrypsin deficiency in COPD patients

Abstract

α1-Antitrypsin (α1-AT) deficiency is an underdiagnosed condition in patients with chronic obstructive pulmonary disease (COPD). The present authors have conducted a nationwide case detection programme of α1-AT deficiency in unselected patients with COPD using dried blood spots. The first phase analysed samples from 971 patients by determining α1-AT concentrations and identifying the deficient Z allele by genotyping using rapid real-time PCR. The second phase analysed 1,166 samples with α1-AT concentrations and identified both the S and the Z allele, but only in samples with low α1-AT concentrations. A total of eight (0.37%) individuals with the severe deficiency PIZZ were detected. In addition, three patients were identified with the PiSZ genotype in the second phase (0.3%). The global cost of the programme was €41,512, which represents €19.42 per sample and €5,189 per PiZZ detected. A sensitivity analysis demonstrated that performing Z genotype to all samples would have resulted in increased costs of €28 per sample and €7,479.5 per PiZZ case identified. In conclusion, a case detection programme of α1-antitrypsin deficiency in patients with chronic obstructive pulmonary disease using dried blood spots is feasible and at a reasonable cost per case detected. Diagnostic yield and costs depend largely on inclusion criteria and the protocol for processing of samples. Copyright©ERS Journals Ltd 2005.