ARUP's Laboratory Test Directory

Alpha-1-Antitrypsin (SERPINA1) Enzyme Concentration and 2 Mutations with Reflex to Alpha-1-Antitrypsin Phenotype : 0051256
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Additional Technical Information
  


Mnemonic: A1A GENO

Ordering Recommendation: Diagnostic testing for alpha-1-antitrypsin deficiency or carrier screening for alpha-1-antitrypsin deficiency.
Methodology: Immunoturbidimetry/Polymerase Chain Reaction/Fluorescence Monitoring/Isoelectric Focusing
Performed: Mon, Thu
Reported: 2-10 days
Specimen Required: Collect: Serum separator tube AND lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation: Allow serum to clot completely at room temperature. Separate serum from cells ASAP or within 2 hours of collection. Transport 0.5 mL serum AND 3 mL whole blood. (Min: 0.5 mL serum AND 0.5 mL whole blood)

Storage/Transport Temperature: Refrigerated.

Stability (collection to initiation of testing): Serum: Ambient: 8 hours; Refrigerated: 5 days; Frozen: 2 weeks
Whole Blood: Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Reference Interval:
Test Number Components Reference Interval
0050001Alpha-1-Antitrypsin 100-200 mg/dL
Alpha-1-Antitrypsin S/Z Mutations By report
Alpha-1-Antitrypsin Phenotype By report

Interpretive Data: Background Information for A1A (SERPINA1) Enzyme Concentration and 2 Mutations with Reflex to A1A Phenotype:
Characteristics: Coughing, wheezing, chronic obstructive pulmonary disease, emphysema, cirrhosis.
Incidence: 1 in 3000 to 1 in 5000.
Inheritance: Autosomal recessive.
Cause: Mutations in the AAT glycoprotein gene on chromosome 14q31-32.3; homozygosity for the Z allele is the most common cause.
Clinical Sensitivity: 95 percent.
Mutations Detected: S allele (c.791A>T) and Z allele (c.1024G>A).
Methods: Genotyping performed by PCR followed by fluorescent probe melting analysis; AAT protein concentration measured using immunoturbidmetric assay; phenotyping performed by isoelectric focusing. Genotyping and AAT serum protein concentration determination are performed on all specimens. Protein phenotyping is performed on specimens that have AAT serum concentrations of less than 100 mg/dL and are heterozygous for either the S or Z allele by genotyping. In addition, protein phenotyping is performed on specimens that have serum protein concentrations of less than 100 mg/dL and do not contain either S or Z alleles by genotyping. Isoelectric focusing is not performed on specimens that are homozygous for deficiency alleles (ZZ, SZ, or SS) by genotyping.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Mutations other than those targeted in S allele (c.791A>T) and Z allele (c.1024G>A) will not be detected; analytic sensitivity may be compromised by rare primer site mutations.

This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.



Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS
Note: Alpha-1-antitrypsin serum protein concentration determination and A1A genotyping are performed on all specimens. If two deficiency alleles (ZZ, SZ, or SS) are detected, then no further testing will be added. If the protein concentration is less than 100 mg/dL and only one or no deficiency allele is detected by A1A genotyping, then phenotyping will be added. Additional charges apply.
CPT Code(s): 82103, 81332;
If reflexed, add 82104
Cross References: Alpha 1 Antitrypsin Genotype (Alpha-1-Antitrypsin (SERPINA1) Enzyme Concentration and 2 Mutations with Reflex to Alpha-1-Antitrypsin Phenotype)