Alpha-1-Antitrypsin (SERPINA1) Enzyme Concentration and 2 Mutations with Reflex to Alpha-1-Antitrypsin Phenotype
Preferred test to identifiy alpha-1-antitrypsin deficiency and causative DNA and protein variants.
Immunoturbidimetry/Polymerase Chain Reaction/Fluorescence Monitoring/Isoelectric Focusing
Serum separator tube AND lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
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)
Serum: Ambient: 1 week; Refrigerated: 3 months; Frozen: 3 months (avoid repeat freeze/thaw cycles)
Whole Blood: Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month.
|0050001||Alpha-1-Antitrypsin||Effective November 17, 2014
Background Information for A1A (SERPINA1) Enzyme Concentration and 2 Mutations with Reflex to A1A Phenotype:
Characteristics of Alpha-1-Antitrypsin (AAT) Deficiency: Coughing, wheezing, bronchiectasis, chronic obstructive pulmonary disease, emphysema, and cirrhosis.
Incidence: 1 in 3000 to 5000 North American individuals.
Inheritance: Autosomal recessive.
Cause: Two pathogenic mutations in the SERPINA1 gene on opposite chromosomes.
Clinical Sensitivity: 95 percent.
Mutations Tested: 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 electrophoresis. Genotyping and AAT serum protein concentration determination are performed on all specimens. Protein phenotyping is only performed on specimens that have AAT protein concentrations of less than 90 mg/dL and are not homozygous or compound heterozygous for the S or Z deficiency alleles by genotyping..
Analytical Sensitivity and Specificity: 99 percent.
Limitations: SERPINA1 mutations, other than the S (c.791A>T) and Z (c.1024G>A) alleles, will not be detected. Diagnostic errors can occur due to rare sequence variations.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.
Laboratory Developed Test (LDT)
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 90 mg/dL and only one or no deficiency allele is detected by A1A genotyping, then phenotyping will be added. Additional charges apply.
82103; 81332; if reflexed, add 82104
|Component Test Code*||Component Chart Name||LOINC|
|0051259||Alpha-1-Antitrypsin S Allele||1829-1|
|0051260||Alpha-1-Antitrypsin Z Allele||1831-7|
|2001289||Alpha-1-Antitrypsin Genotype Specimen||31208-2|
- Alpha 1 Antitrypsin
- Alpha 1 Antitrypsin Genotype
- Alpha one Antitrypsin
- Alpha1-Protease Inhibitor
- Pi Typing
- Protease I