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Test Code A1ALC Alpha-1-Antitrypsin Proteotype S/Z, LC-MS/MS, Serum

Important Note

Order this test when a Alpha 1-antitrypsin Phenotype is requested. It includes the A1-antitrypsin.

1. Order as a .Mayo Misc

2. Code = AALC

2. Test Name = A1AT Proteotype S/Z, LC-MS/MS, S

Useful For

Identification of homozygous and heterozygous S and Z proteotypes of alpha-1-antitrypsin deficiency

Profile Information

Test ID Reporting Name Available Separately Always Performed
A1ASZ A1AT Proteotype S/Z, LC-MS/MS No Yes
AATP Alpha-1-Antitrypsin, S Yes, (order AAT) Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
A1APR Alpha-1-Antitrypsin Phenotype, S Yes, (order A1APP) No

Testing Algorithm

If the mass spectrometry proteotype and quantitative serum level are discordant, then phenotyping will be added and performed at an additional charge.

 

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

Reporting Name

A1AT Proteotype S/Z, LC-MS/MS, S

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 Special Container
Serum Refrigerated (preferred) 28 days
  Ambient  28 days
  Frozen  28 days

Reference Values

ALPHA-1-ANTITRYPSIN:

100-190 mg/dL

 

ALPHA-1-ANTITRYPSIN PROTEOTYPE:

Negative for S and Z phenotype (Non S Non Z)

Interpretation

For each of the possible alpha-1-antitrypsin (A1A) genotypes there is an expected range for the total serum level of A1A. However, a number of factors can influence either the A1A serum level or the A1A proteotype results, including acute illness (A1A is an acute-phase reactant), protein replacement therapy, the presence of other rare variants, or the presence of rare DNA alterations (ie, polymorphisms). When the serum level differs from what is expected for that proteotype (ie, discordant), additional studies are performed to ensure the most appropriate interpretation of test results. Additional follow-up may include A1A phenotyping by isoelectric focusing, obtaining additional clinical information, and DNA sequencing. See Alpha-1-Antitrypsin Testing Result Table.

Clinical Reference

1. Murray JD, Willrich MA, Krowka MJ, et al. Liquid chromatography-tandem mass spectrometry based alpha1-antitypsin (AAT) testing. Am J Clin Clin Pathol. 2021;155(4):547-552

2. Chen Y, Snyder MR, Zhu Y, et al. Simultaneous phenotyping and quantification of alpha-1-antitrypsin by liquid chromatography-tandem mass spectrometry. Clin Chem. 2011;57(8):1161-1168

Day(s) Performed

Monday, Thursday

Report Available

7 to 14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

82103

82542

82104 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
A1ALC A1AT Proteotype S/Z, LC-MS/MS, S 102082-5

 

Result ID Test Result Name Result LOINC Value
AATP Alpha-1-Antitrypsin, S 6771-0
34855 A1AT Proteotype S/Z, LC-MS/MS 49244-7

Method Name

A1ASZ: Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

AATP: Nephelometry

A1APR: Isoelectric Focusing

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

Forms

If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request (T728) with the specimen.