Mold testing is an important tool for assessing potential mold issues in a home or building. However, understanding the results of mold tests can be confusing for those without experience interpreting scientific reports. This guide provides a step-by-step overview on how to properly interpret the various types of mold tests in order to determine if you have a problematic mold situation that requires remediation.
Types of Mold Tests
There are a few main types of mold tests that professionals use to check for mold. Each has its own methodology and interpretation approach.
Air Tests
Air tests involve taking samples of the air to test for the presence of mold spores. Samples are taken using specialized equipment that draws a known volume of air through a cassette holding a spore trap material. That material is later analyzed in a microbiology laboratory under a microscope to identify and count the mold spores collected.
Interpreting Air Test Results
Lab reports for air testing list the specific types of mold found along with the concentration, reported as spores per cubic meter of air (spores/m3). The total number provides an overall measurement of the contamination. Results are then compared to outside samples and guidelines to help determine if your indoor spore levels are higher than desired.
Higher numbers indicate higher levels of mold, raising concern for health issues and problematic growth requiring remediation. Guidelines suggest action is warranted when indoor concentrations are 2 to 3 times higher indoors than outdoors.
Surface Tests
Surface testing uses different sized sterile swabs, wipes, or tape strips pressed onto visibly moldy surfaces or areas suspected of fungal growth underneath. The samples collect and concentrate any mold present for identification at the microscopic level later on.
Interpreting Surface Test Results
Lab reports will specify the mold types found along with a semi-quantitative rating scale noting quantities as “rare, light, moderate, heavy, or very heavy.” Heavier spore deposition suggests an actively growing colony and source within the vicinity. Identification also helps categorize risks from allergenic genera like Aspergillus or toxigenic genera like Stachybotrys chartarum. Remediation is typically recommended whenever mold growth is located.
Bulk/Wall Cavity Testing
This technique requires invasive sampling by cutting or drilling into wall cavities, under materials, or other hidden locations to obtain a portion of the potentially contaminated building materials themselves for lab analysis. Bulk testing is useful for identifying mold behind walls, under flooring, in HVAC systems, etc. Special handling procedures are required for transport to the microbiology laboratory.
Interpreting Bulk Testing Results
Lab analysis uses microscopic visual examination coupled with culturing practices to detect and confirm living mold growth from bulk specimens. Positive lab results for mold from bulk samples indicate hidden colonies that should be remediated, often requiring removal of that material itself during the process. Even dead mold matter can suggest previous or recurring issues.
Factors in Interpreting Any Mold Test Results
While the lab reports present scientific measurements and identification, there are also some additional factors to weigh when interpreting mold testing detroit results for your building and health. Consider the context behind the numbers.
Comparison Samples
Ideally, indoor air or surface samples should be interpreted against baseline measurements of outside air and uncontaminated building materials, when available. Labs will often provide general ranges for typical outdoor concentrations in your region for comparison. Larger differences suggest an indoor source is more likely.
Sampling Variability
Some variability in sampling is always present. Factors like weather conditions, activity levels in rooms, or technique during surface testing can influence the mold levels detected from environment to environment or across different inspectors. Consider repeated testing over time or sampling multiple rooms when necessary.
Symptoms
Pay attention to any health symptoms commonly associated with mold exposure when interpreting your test results. Chronic issues like respiratory problems, headaches, fatigue and nasal congestion may suggest an indoor air quality issue like elevated mold spores. Symptoms combined with positive test findings warrant proper remediation and exposure precautions.
Next Steps After Receiving Mold Testing Results
Once you review your mold inspection report, you’ll need to determine which next actions are necessary based on the findings and recommendations. Here are some common next steps people take after interpreting their mold test results:
Additional Testing
If initial surface sampling identified some mold growth, but extent is unclear, more expansive testing across other areas may be performed to map locations. Air testing could also monitor remediation progress. Consider if further testing is needed to rule out other contaminated zones.
Remediation
Remediation performed by trained professionals is required whenever actively growing mold is detected indoors. All contaminated materials must be cleaned or removed properly. Post remediation verification testing helps confirm spore levels dropped back down to acceptable ranges after the work.
Exposure Precautions
Take precautions to limit exposure if you have confirmed mold problems, especially if you are susceptible with allergies or asthma. This could involve blocking access to affected rooms, wearing PPE masks, running air scrubbers, or temporarily relocating sensitive individuals until after remediation. Consult a doctor if experiencing symptoms.
HVAC Inspections
Identifying problematic mold could indicate moisture issues or deficiencies in your building’s heating, ventilation and air conditioning (HVAC) system promoting fungal growth. Schedule inspection by qualified HVAC professionals when appropriate to identify and remedy root causes.
Properly interpreting your mold testing results involves reviewing the scientific lab analyses, weighing contextual factors at your site, evaluating potential health impacts, and determining any necessary corrective actions like remediation or HVAC repairs. Refer to this guide to feel informed examining your own mold testing reports. Reach out to industrial hygienists or medical professionals as needed with any questions or concerns.
