Table 3

Comparison between two published ranges (5th–95th percentiles) of α1-antitrypsin serum levels according to different phenotypes (PI),1 one in μM and one in g/litre,6 and the range, according to different genotypes (PI*), as deduced by our analysis2

Phenotype–genotype	Units	Reference ranges1	Present paper2
PI MM–PI*MM	μM	20–48	20.2–31.5
PI MM–PI*MM	g/l	1.50–3.50	1.05–1.64
PI SS–PI*SS	μM	15–33	14.0–20.4
PI SS–PI*SS	g/l	1.00–2.00	0.73–1.06
PI MZ–PI*MZ	μM	17–33	12.7–19.2
PI MZ–PI*MZ	g/l	0.90–2.10	0.66–1.00
PI SZ–PI*SZ	μM	8–16	9.4–12.7
PI SZ–PI*SZ	g/l	0.75–1.20	0.49–0.66

The g/litre values in our analysis were mathematically converted to μM, based on a molecular weight of 52 kDa. Note that the PI*MS data are not present because this genotype was not included in the original American Thoracic Society/European Respiratory Society guidelines.