Atlanta, GA — In the indoor environment, settled dust may contain allergens. The nature, type and contents of these allergens may vary depending on the season and location. The assessment of allergens in a house dust sample is an essential step for allergen-avoidance and provides information essential for allergen-reducing measures, in addition to managing the indoor environment from a health and hygiene point of view.
Most common allergens in this category include but are not limited to
• Dust mite (Der p 1, Der f 1P)
• Cockroach (Bla g 2)
• Animals (cat (Fel d 1), and dog (Can f 1) etc).
Exposure to these substances, even in small amounts, can trigger allergenic symptoms/disorders. Common symptoms of a house dust allergy include, but are not limited to, sneezing, itchy or watery eyes, nasal congestion and a runny nose. These signs appear as a result of production of immunoglobulin E (IgE) antibodies in a sensitive individual upon the exposure of dust allergens. In fact, IgE binds to mast cells in the mucosa in eye conjunctiva, nose, throat, and bronchi, and trigger a release of histamine. Histamine causes dilation of vessels in mucosa, and secretion of mucus from mucous glands, resulting in mucosal swelling and mucus secretion, which gives allergenic symptoms.
Successful management of allergies due to house dust is a two-fold approach (i.e. clinical diagnosis of the allergy sufferer and environmental monitoring of the dwelling). The clinical evaluation of a patient includes symptom history, blood tests, IgE levels, evaluation of suspected allergens (skin prick or patch test), etc. where as environmental monitoring reveals the identification and quantification of allergen load in house dust.
Culture (Bioaerosols) or non-culture (spore trap analysis) based methods and Polymerase Chain Reaction (PCR) are often used for enumerating allergens of the indoor environment.
However, enzyme immunoassay (ELISA) of air or dust samples has been the gold standard for assessing indoor allergens. ELISA kits have been used for analyzing indoor allergens in house dust for years, although it is costly, time consuming and allergen specific. Recently, Multiplex Array (MARIA™) for Indoor Allergens has been introduced which evaluates five to eight most common allergens/sample in house dust.
The array simultaneously measures the mite allergens Der p 1, Der f 1 and Mite Group 2, animal allergens of cat (Fel d 1), dog (Can f 1), rat (Rat n 1) and mouse (Mus n 1) as well as cockroach (Bla g 2). The Multiplex Array provides improved assay performance (increased sensitivity, accuracy and precision) in a high throughput system with substantial time and cost savings. Concentration of identified allergens from indoor dust is reported as μg/gram.
How Multiplex Array Works
Multiplex Array uses technology in which micro spheres (bead) of 5.6 μm in diameter made out of polystyrene are labeled with internal fluorescent dyes. The hundred-bead sets can be distinguished by their internal dye ratio. Micro spheres are covalently coupled with capture monoclonal antibodies. During the assay, beads bearing the desired capture antibodies are combined and incubated with an allergen sample. Bound allergens are detected using biotinylated mAb and a streptavidin-conjugated fluorophore. During measurement, micro spheres are drawn into the optical path of the instrument, where a red laser identifies beads by their internal color as bearing a specific allergen. A green laser quantifies the intensity of the external fluorescent signal, i.e. the amount of streptavidin-conjugated fluorophore, and thereby quantifies the amount of allergen. The array is sensitive and has detection limits of ~0.1ng/ml.
Environmental bulk/dust samples are acceptable for Multiplex Array analysis. Dust samples from the indoor environment can be collected in a dust sock House Dust Allergen (HDA) Kit which can be purchased at a number of on-line dealers including Grainger, PE Equipment, Lab Safety, Carrier, Allergy Buyers Club, Allen, among others. The dust sock (comes with the House Dust Allergen (HAD) kit) is attached to the hose of a vacuum cleaner, against the flow of the air. The suspect area is vacuumed. Then, the dust sock, containing the collected dust, is carefully removed and mailed to the laboratory in a clean and unused zip lock bag along with the completed chain of custody.
Advantage of Multiplex Array:
• Multiple allergen tests (up to 8- allergens) in one environmental sample. Significantly reduces the sample collection time.
• More sensitive in comparison to other methods.
• Use of Universal Allergen Standard generates superior data.
• Statistically superior results with less variation
House Dust Allergen (HDA) Kit:
House Dust Allergen test kits can be purchased from Indoor Airtest or call: 800-422-7873 ext. 404.
About Environmental Diagnostics Laboratory (EDLab):
Alan Wozniak founded Pure Air Control Services, Inc. in 1984 as a small mechanical contracting firm and has since set the industry standard for indoor environmental quality
diagnosis, environmental laboratory and remediation. Pure Air Control Services has serviced more than 600 million square feet of indoor environments in over 10,000 facilities.
The Environmental Diagnostics Laboratory (EDLab) (established in 1992) at Pure Air Control Services (PACS) is an environmental lab offering complete and
comprehensive indoor environmental microbiology laboratory services. They include: microbiology, aerobiology, chemistry, allergen assays and microscopy designed to meet all your indoor air needs. EDLab supports IAQ investigations by assisting with strategic sampling plan development and supplying media collection equipment while performing a wide range of environmental analyses.
The company’s expanding client roster includes the General Services Administration (GSA);US Army Corps of Engineers (USACE), Allstate Insurance; Carrier Air Conditioning; US Naval Air Warfare Center, Orlando; and Naval Air Station – King’s Bay, Georgia, and many other Fortune 500 companies, school boards, and city, state, and county governments, making Pure Air Control Services/EDLab the reliable industry leader in IAQ.