Guidelines for Diagnosis and Management of Severe Alpha‑1 Antitrypsin Deficiency

Diagnostic Testing

DNA sequencing of SERPINA1 exons 2‑5 is the gold‑standard test for confirming severe AAT deficiency and should be performed in all suspected patients【1】.
Adults with asthma that began in adulthood and shows persistent airflow obstruction should be screened for AAT deficiency【3】.
Individuals with unexplained bronchiectasis warrant AAT testing【4】.
First‑degree relatives of persons with pathogenic SERPINA1 variants should receive genetic testing and counseling【5】.

High clinical suspicion (immediate DNA sequencing):
- Onset of COPD before age 40【8】.
- COPD with ≤10 pack‑year smoking history【8】.
- Basal pan‑lobular emphysema on imaging【2】.
- History of perinatal jaundice【2】.
Moderate clinical suspicion (serum AAT level first, then sequencing if needed):
- Unexplained bronchiectasis【4】.
- Adult‑onset asthma with persistent obstruction【4】.
- Granulomatosis with polyangiitis or panniculitis【2】.

High suspicion pathway: Proceed directly to SERPINA1 DNA sequencing, bypassing serum AAT measurement, to avoid misclassification and to detect >300 known and dysfunctional variants (e.g., Pi*F) that may have normal serum levels【7】.
Moderate suspicion pathway:
Pitfalls: Serum AAT is an acute‑phase reactant and can fluctuate during inflammation, leading to false‑negative results; repeat testing shows poor reproducibility, especially for intermediate deficits【3】.

Offer counseling and testing to all first‑degree relatives of individuals with abnormal SERPINA1 genotypes, regardless of heterozygosity or homozygosity【5】.
Patients identified with novel SERPINA1 mutations should be referred to expert reference centers for functional characterization【5】.

Conditional recommendation to initiate intravenous AAT augmentation when all of the following are present:

The RAPID trial demonstrated that regular intravenous AAT therapy preserves CT lung density (high‑quality evidence)【2】.
The same trial showed a reduction in mortality, although the evidence quality was rated very low【2】.
Delayed diagnosis (average 5.3 years after symptom onset, with baseline FEV₁ ≈52 % predicted) is associated with poorer overall and transplant‑free survival【6】【7】.

Pharmacologic therapy with bronchodilators and inhaled corticosteroids per standard COPD guidelines【2】.
Annual influenza vaccination and pneumococcal immunization【3】.
Self‑management education programmes【7】.
Supplemental oxygen for hypoxemic patients【7】.
Comprehensive case management to coordinate care【8】.

Absolute avoidance of tobacco smoking【8】.
Minimize exposure to high‑risk environmental airway irritants (e.g., occupational dusts, chemicals)【4】.
General counseling to promote a balanced diet, regular physical activity, and pulmonary hygiene【6】.

Lung disease progression: Perform periodic spirometry; CT densitometry may be used selectively for research or high‑risk cases【6】.
Liver disease: Conduct regular assessments for cirrhosis and hepatocellular carcinoma in patients with AAT deficiency【6】.
Infections: Monitor for increased susceptibility to pulmonary infections, including mycobacterial disease【6】.

Evaluate eligible patients with advanced disease for lung‑volume‑reduction surgery or lung transplantation【8】.

Genotyping alone is insufficient: Targeted panels detect only common PiS and PiZ alleles; full DNA sequencing captures all >300 variants, including dysfunctional ones with normal serum levels【5】【3】.
Serum AAT levels should not be the sole diagnostic tool: They miss dysfunctional variants and are influenced by acute‑phase reactions【4】【3】.
Do not postpone testing: Reliance on clinical suspicion alone leads to missed or delayed diagnoses; systematic testing improves detection rates【6】【7】.