Workup of individuals with suspected disorders such as familial chronic obstructive lung disease
Diagnosing alpha-1-antitrypsin deficiency
For more information see Alpha-1-Antitrypsin-A Comprehensive Testing Algorithm.
Nephelometry
Alpha 1 Antitrypsin
Anti-Alpha-1-Trypsin
Prolastin
A1A
AAT (Alpha-1-Antitrypsin)
Alpha-1-Antitrypsin Reflex
AAT
For more information see Alpha-1-Antitrypsin-A Comprehensive Testing Algorithm.
Serum
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
If not ordering electronically, complete, print, and send 1 of the following with the specimen:
-Gastroenterology and Hepatology Test Request (T728)
-General Request (T239)
0.5 mL
Gross hemolysis | OK |
Gross lipemia | Reject |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 28 days | |
Ambient | 28 days | ||
Frozen | 28 days |
Workup of individuals with suspected disorders such as familial chronic obstructive lung disease
Diagnosing alpha-1-antitrypsin deficiency
For more information see Alpha-1-Antitrypsin-A Comprehensive Testing Algorithm.
Alpha-1-antitrypsin (A1A) is the most abundant serum protease inhibitor, and it inhibits trypsin and elastin as well as several other proteases. The release of proteolytic enzymes from plasma onto organ surfaces and into tissue spaces results in tissue damage unless inhibitors are present. Congenital deficiency of A1A is associated with the development of emphysema at an unusually early age and with an increased incidence of neonatal hepatitis, usually progressing to cirrhosis.
For more information see Alpha-1-Antitrypsin-A Comprehensive Testing Algorithm.
100-190 mg/dL
Patients with serum levels less than 70 mg/dL may have a homozygous deficiency and are at risk for early lung disease. Alpha-1-antitrypsin proteotype testing should be done to confirm the presence of homozygous deficiency alleles.
If clinically indicated, patients with serum levels less than 125 mg/dL should have proteotype testing in order to identify heterozygous individuals. Heterozygotes do not appear to be at increased risk for early emphysema.
Low alpha-1-antitrypsin (A1A) levels may result from liver disease, and A1A proteotype testing should be done to confirm A1A deficiency disease.
A1A is an acute-phase reactant, and any inflammatory process will elevate serum A1A levels.
Quantitation of specific proteins by nephelometric means may not be possible in lipemic sera due to the extreme light scattering properties of the specimen. Turbidity and particles in the specimen may result in extraneous light scattering signals, resulting in variable specimen analysis.
1. Tejwani V, Stoller JK: The spectrum of clinical sequelae associated with alpha-1 antitrypsin deficiency. Ther Adv Chronic Dis. 2021 Jul;12_suppl. doi: 10.1177/2040622321995691
2. Patel D, McAllister SL, Teckman JH: Alpha-1 antitrypsin deficiency liver disease. Transl Gastroenterol Hepatol. 2021 Apr 5;6:23. doi: 10.21037/tgh.2020.02.23
3. Donato LJ, Snyder MR, Greene DN: Measuring and interpreting serum AAT concentration. Methods Mol Biol. 2017;1639:21-32. doi: 10.1007/978-1-4939-7163-3_3
In this Siemens Nephelometer II method, the light scattered onto the antigen-antibody complexes is measured. The intensity of the measured scattered light is proportional to the amount of antigen-antibody complexes in the sample under certain conditions. If the antibody volume is kept constant, the signal behaves proportionally to the antigen volume.
A reference curve is generated by a standard with a known antigen content on which the scattered light signals of the samples can be evaluated and calculated as an antigen concentration. Antigen-antibody complexes are formed when a sample containing antigen and the corresponding antiserum are put into a cuvette. A light beam is generated with an LED, which is transmitted through the cuvette. The light is scattered onto the immuno-complexes that are present. Antigen and antibody are mixed in the initial measurement, but no complex is yet formed. An antigen-antibody complex is formed in the final measurement.
The result is calculated by subtracting value of the final measurement from the initial measurement. The distribution of intensity of the scattered light depends on the ratio of the particle size of the antigen-antibody complexes to the radiated wavelength.(Unpublished Mayo method; instruction manual: Siemens Nephelometer II. Siemens, Inc; Version 2.3, 2008; Addendum to the Instruction Manual 2.3, 08/2017)
Monday through Friday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
82103
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
AAT | Alpha-1-Antitrypsin, S | 6771-0 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
AAT | Alpha-1-Antitrypsin, S | 6771-0 |