What are the Alpha-1 (Alpha-1 antitrypsin) lab results?

From the Guidelines

Alpha-1 Antitrypsin Lab Results

The alpha-1 antitrypsin serum level is typically measured at 11.0 M 1.

Key Points

• The level of evidence for laboratory testing, including alpha-1 antitrypsin serum levels, is considered II-2 1, indicating that the indication for treatment is independent of the phenotype and based on the level and presence of obstructive lung disease.
• The serum level should exceed the 35% predicted threshold, which is above 15 M on Day 7 immediately before the next infusion 1.
• Augmentation therapy may be considered for patients with alpha-1 antitrypsin deficiency, with a typical dosing regimen of 250 mg of AAT per kilogram administered monthly 1.
• It is essential to monitor patients' lung function and density, as well as their response to treatment, to adjust the therapy as needed 1.

Important Considerations

• Patients with normal or nearly normal pulmonary function can be treated if they experience a rapid decline in lung function (FEV1 ≥ 120 ml/yr) 1.
• Adverse reactions to AAT concentrate are rare, but may include fever, chills, dyspnea, and anaphylactic reactions 1.

From the FDA Drug Label

The median trough Alpha1-PI values for Weeks 7-12 for subjects receiving GLASSIA were 14.5 microM (range: 11.6 to 18.5 microM) for antigenic and 11.8 microM (range: 8.2 to 16.9 microM) for functional Alpha1-PI. Eleven of 33 subjects (33.3%) receiving GLASSIA had mean steady-state functional Alpha1-PI levels below 11 microM. All subjects receiving GLASSIA had mean serum trough antigenic Alpha1-PI levels greater than 11 microM during Weeks 7-12 GLASSIA augmentation therapy resulted in a statistically significant increase in antigenic Alpha1-PI levels in ELF (median change=0.5 μM; geometric mean ratio=5.4, p<0.001; Table 6). Functional Alpha1-PI levels in ELF also showed a statistically significant increase in response to GLASSIA (median change=0.3 μM, geometric mean ratio=2.3, p<0.001; Table 6)

The Alpha-1 antitrypsin lab results show that:

• The median trough antigenic Alpha1-PI levels were 14.5 microM (range: 11.6 to 18.5 microM)
• The median trough functional Alpha1-PI levels were 11.8 microM (range: 8.2 to 16.9 microM)
• 33.3% of subjects had mean steady-state functional Alpha1-PI levels below 11 microM
• All subjects had mean serum trough antigenic Alpha1-PI levels greater than 11 microM during Weeks 7-12
• GLASSIA augmentation therapy resulted in a statistically significant increase in antigenic and functional Alpha1-PI levels in ELF 2, 2, 2

From the Research

Alpha-1 Antitrypsin Lab Results

The Alpha-1 antitrypsin (A1AT) lab results typically involve the measurement of A1AT concentration and identification of specific alleles by genotyping and phenotyping.

• The A1AT concentration can be measured using various methods, including:
  • Immunoturbidimetric assay 3
  • Nephelometry 4, 5, 6
  • LC-MS/MS (liquid chromatography-tandem mass spectrometry) 5
• The A1AT phenotype can be determined using:
  • Isoelectric focusing (IEF) followed by immunofixation (IEF-IF) 3, 4, 5, 6
  • Luminex xMAP technology using Progenika A1AT Genotyping Test 7
• Genotyping can be performed using:
  • Melting curve analysis using real-time PCR 3, 4
  • PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) method 3
  • Gene sequencing 3, 7, 6
• The lab results can be interpreted as follows:
  • Normal A1AT concentration: 0.9-1.7 g/L (using nephelometry) 4
  • Deficient A1AT concentration: less than 0.30 g/L (using immunoturbidimetric assay) 3
  • Phenotype: Pi MM (normal), Pi MZ (heterozygous), Pi ZZ (homozygous) 3, 4
  • Genotype: identification of specific alleles, such as S and Z alleles 3, 4, 7