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Test Code LAB2189 Alpha-1-Antitrypsin Phenotype, Serum

Additional Codes

A1APP

Useful For

Identification of homozygous and heterozygous phenotypes of the alpha-1-antitrypsin deficiency

Profile Information

Test ID Reporting Name Available Separately Always Performed
A1AP2 Alpha-1-Antitrypsin Phenotype No Yes
AATP Alpha-1-Antitrypsin, S Yes, (Order AAT) Yes

Testing Algorithm

For information see Alpha-1-Antitrypsin-A Comprehensive Testing Algorithm.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1.25 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 28 days
  Ambient  28 days
  Frozen  28 days

Reference Values

ALPHA-1-ANTITRYPSIN

100-190 mg/dL

 

ALPHA-1-ANTITRYPSIN PHENOTYPE

The interpretive report will identify the alleles present. For rare alleles, the report will indicate whether they have been associated with reduced quantitative levels of alpha-1-antitrypsin.

Day(s) Performed

Monday through Friday

CPT Code Information

82103

82104

LOINC Code Information

Test ID Test Order Name Order LOINC Value
A1APP Alpha-1-Antitrypsin Phenotype 32769-2

 

Result ID Test Result Name Result LOINC Value
AATP Alpha-1-Antitrypsin, S 6771-0
8166 Alpha-1-Antitrypsin Phenotype 32769-2

Interpretation

There are greater than 40 alpha-1-antitrypsin (A1A) phenotypes (most of these are associated with normal quantitative levels of protein). The most common normal phenotype is M (M, M1, or M2), and greater than 90% of individuals of European descent are genetically homozygous M (MM).

 

Alpha-1-antitrypsin deficiency is usually associated with the Z phenotype (homozygous ZZ), but SS and SZ are also associated with decreased A1A levels.

Method Description

Alpha-1-Antitrypsin Phenotype

Phenotyping is done by isoelectric focusing in agarose gels. Certain alleles are associated with various serum levels of alpha-1-antitrypsin, and their respective proteins exhibit differential mobility on electrophoresis.(Package insert: Hydragel 18 A1AT Isofocusing. Sebia. 01/2020)

 

Alpha-1-Antitrypsin

In this Siemens Nephelometer II method, the light scattered by 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 a light emitting diode (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 formed yet. 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.(Instruction manual: Siemens Nephelometer II. Siemens, Inc; V 2.4, 07/2019; Addendum to the Instruction Manual 2.3, 08/2017)

Report Available

2 to 6 days

Reject Due To

Gross hemolysis OK
Gross lipemia Reject
Gross icterus OK

Method Name

A1AP2: Isoelectric Focusing

AATP: Nephelometry

Secondary ID

26953

Forms

If not ordering electronically, complete, print, and send 1 of the following with the specimen:

-Gastroenterology and Hepatology Test Request (T728)

-General Request (T239)