Diagnostic Test Directory

Molecular Genetics Laboratory

CHOP in the News

Clinical Lab Products quotes Avni Santani, PhD, Scientific Director, Molecular Genetics Laboratory, in a story about next-gen sequencing. Read the story »

Laboratory Update

Testing for the Noonan spectrum of disorders is now available at the Molecular Genetics Laboratory. Learn more about Noonan spectrum testing »

Asthma (ADRB2 Genotype Assay for R16G)

  • LIS Mnemonic: MBADRB2


    Collect whole blood in a purple top (EDTA) tube (preferred). Extracted DNA is also acceptable.

    Volume Required

    5 ml whole blood or 1 ug DNA

    Minimum Required

    3 mls


    Refrigerate sample until shipment. Send the sample at room temperature with overnight delivery for receipt Monday through Friday within 24 hours of collection.


    Whole blood can be refrigerated until shipment.

    Unacceptable conditions

    Heparinized specimens, severely hemolyzed specimens, frozen, clotted or possibly commingled specimens, blood in non-sterile or leaky containers, mislabeled or inappropriately labeled specimens.

    Specimen Handling

    Do not heat, freeze or centrifuge blood before shipment. Refrigerate sample until shipment.

Days Performed

Mon - Fri 9:00am to 4:00pm


10 days



Disease Information

Clinical Features:

Clinical indications for ADBR2 genotype analysis in asthma patients includes active asthma requiring inhaled ß-adrenergic agonists (ie, albuterol, isoetharine, metaproterenol, pirbuterol, and terbutaline) and /or an apparent decrease in effectiveness of these drugs for controlling symptoms.

Molecular Genetics:

The ADRB2 gene is located on chromosome 5p31-q32. The mutation is a single nucleotide polymorphism (SNP) at nucleotide 46 (c.46G>A). This SNP has allele frequencies of 0.324 (for the A allele) and 0.676 (for the G allele). The ADRB2 gene encodes the beta 2-adrenergic receptor which is a member of the G protein-coupled receptor super family. A polymorphism at codon 16 of the ADRB2 gene has been associated with altered airway response to regularly inhaled albuterol in mild asthmatics. This SNP results in a codon for etiher arginine or glycine at amino acid position 16. The Arg/Arg genotype has been associated with a decrease in peak expiratory flow compared to patients with either the Gly/Gly or Gly/Arg genotypes with regular use of the beta agonist albuterol.

Test Methods:

We detect the c.46G>A change using an allelic discrimination assay. The patient’s sample is compared to homozygous, heterozygous, and known normal controls.

Detection Rate:

The detection rate for allelic discrimination is 100% of ADRB2 genotypes at nucleotide 46.


Test results with interpretation will be mailed and/or faxed to the referring physician or send out lab following completion of the test. Additional reports will be provided as requested.


The clinical utility of the assay is in better management of asthmatic patients (ie, altering the frequency with which drugs are administered or switching from one class of drugs to another. The results of this assay, however, should not be used as the sole or major determinant in managing patient care.

Search Lab Test Directory

Search by disease or test name

View a full list of all lab tests

Contact Us

Ask for more information about our laboratory services.