Laboratory: Clinical Immunology
Test Name:
ALPHA-1-ANTITRYPSIN PROTEOTYPE - (S)
Test Code: AATP
Clinical Information:
The diagnosis of A1A deficiency is initially made by quantitation of protein levels in serum followed by determination of specific allelic variants by isoelectric focusing (IEF).  While there are many different alleles in this gene, only 3 are common.  The 3 major alleles include:  M (full functioning, normal allele), S (associated with reduced level of protein), and Z (disease-causing mutation associated with liver disease and premature emphysema).  The S and Z alleles account for the majority of the abnormal alleles detected in affected patients.  As a codominant disorder, both alleles are expressed.  An individual of SZ or S-null genotype may have a small increased risk for emphysema (but not liver disease) due to slightly reduced protein levels.  On the other hand, an inividual with the ZZ genotype is at greater risk for early onset liver disease and premature emphysema.
Collection Devices:
Specimen Required:
Serum: 1.0 mL
Pediatric Serum: 0.5 mL
Referral:
Requisition:
Reference Values:
S Mutation  -  Negative
Z Mutation  -  Negative
Availability:
Within 10 Days
See Also:
More Information:
Record under "Additional Tests"
If sample requirements are met, patients with quantitative results below 0.900 g/L will be sent to In-Common Laboratories for Proteotype testing.  If the mass spectrometry proteotype and quantitative serum levels are discordant, phenotyping will be added and reported.
In-Common Laboratories test code:  A1ALC
Note:  If patient is a first degree relative/spouse of a known Alpha-1-Antitrypsin deficient individual, this must be included on the requisition to guarantee specimen is processed.