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HelpEpic Test Code LAB4948 Alpha-1-Antitrypsin Enzyme Concentrarion with Reflex to A1 Antitrypsin Phenotype
Additional Codes
ARUP:0051256
Ordering Recommendation
Preferred test to identifiy alpha-1-antitrypsin deficiency and causative DNA and protein variants.
Specimen Type
Serum and Whole Blood
Collection Container
Serum separator tube AND lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
Blood Tube Draw Volume
Min 50% draw volume
Minumum Volume to Submit for Testing
0.5 mL serum AND 3 mL whole blood
Specimen Stability
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.
Specimen Transport
Refrigerated.
Causes for Rejection
Mislabeled or Unlabeled specimen
Less than 50% draw for Vacutainer tubes
Days of Analysis
Varies
Turn Around Time
2-10 days
Reference Range
Alpha-1-Antitrypsin- 90-200 mg/dL
Interpretive Data
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.
Additional Information
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.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com
Methodology
Immunoturbidimetry/Polymerase Chain Reaction/Fluorescence Monitoring/Isoelectric Focusing
CPT Code(s)
82103; 81332; If reflexed add 82104
Last Updated
6-Mar-18