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How do labs test for mold?
Testing for mold in a laboratory typically involves identifying the type, concentration, and potential toxicity of mold spores or fragments present in a sample. Labs use a variety of methods depending on the sample type (air, surface, or bulk material) and the purpose of the test. Here’s an overview:
1. Sample Collection
Air Samples: Collected using spore traps or impaction samplers that draw air through a sticky surface or filter.
Surface Samples: Obtained using tape lifts, swabs, or by collecting dust.
Bulk Samples: Pieces of material (e.g., drywall, insulation) are sent for testing.
2. Microscopic Analysis
Direct Microscopy: Samples are examined under a microscope to identify mold spores and hyphal fragments based on size, shape, and color.
Staining Techniques: Special dyes like lactophenol cotton blue highlight fungal structures for easier identification.
3. Culture Testing
Samples are cultured on specific growth media (e.g., malt extract agar or Sabouraud agar) to grow colonies of viable mold.
Identifying colonies helps determine the species and quantify viable mold in the sample.
4. Molecular and Biochemical Techniques
PCR (Polymerase Chain Reaction): Detects and identifies mold DNA, offering highly sensitive and specific results.
Mycotoxin Analysis: Some labs test for mycotoxins, toxic compounds produced by certain molds, using methods like liquid chromatography-mass spectrometry (LC-MS).
5. Airborne Spore Count
Air samples are analyzed for the concentration of mold spores per cubic meter of air, which helps assess indoor air quality.
6. Identification of Species
Morphological identification under a microscope or DNA sequencing techniques can pinpoint specific mold species.
7. Environmental Conditions Testing
Labs may also measure moisture levels, humidity, and temperature of samples to determine environmental factors contributing to mold growth.
Reporting Results
The lab provides a detailed report including:
Types of molds present (e.g., Aspergillus, Penicillium, Stachybotrys).
Quantitative data (e.g., number of spores per cubic meter of air or per sample area).
Health risk assessments if applicable.
Lab results are typically used alongside environmental assessments to determine remediation strategies.