Mold Testing for Lexington Properties —
Source-Driven Protocol, Accredited Lab

Mold spores are naturally present in outdoor air everywhere — the outdoor concentration varies enormously by season, weather, and regional vegetation, and it's different on a dry fall afternoon than on a humid summer morning in the same Lexington location. Without knowing what the outdoor concentration is on the same day as the indoor sample, you can't determine whether the indoor count is elevated relative to background. A count of 500 Cladosporium spores/m³ might be normal if the outdoor count that day is 600, or it might indicate a problem if the outdoor count is 40. The comparison is what produces a finding — not the raw number alone.

ERMI (Environmental Relative Moldiness Index) uses qPCR analysis on settled floor dust to identify and quantify 36 specific mold species. Because settled dust accumulates over time, ERMI reflects the historical mold load in the property — not just what's airborne at the moment of sampling. This makes ERMI appropriate for: properties where current air sampling is normal but past mold events are suspected; post-remediation verification when you want to confirm long-term improvement, not just current-condition clearance; and properties where current airborne counts fluctuate with weather and ventilation in ways that make point-in-time sampling unreliable.

Yes — significant. The differences that matter: (1) Does the sampler collect an outdoor baseline? Without it, results are uninterpretable. (2) Is chain of custody maintained from sample collection to lab receipt? Without it, results aren't defensible in insurance or legal contexts. (3) Is the lab accredited? Non-accredited lab results aren't accepted by insurance carriers or courts. (4) Does the report match the use case? A real estate report, a health-complaint report, and an insurance report have different required elements. (5) Is the protocol AIHA-method compliant? Non-standard sampling flow rates or durations produce biased results.

Minimum for a meaningful result: one outdoor comparative, plus indoor samples at areas of concern and at least one unaffected area. A typical Lexington, WA single-family home inspection involves three to five samples total: one outdoor, one to two in suspected problem areas, one in an unaffected area. Larger properties, multi-unit buildings, or commercial properties require samples per zone or unit. We scope the sampling protocol based on your specific property size and what question we're trying to answer — not a default package.

Insurance-ready test documentation includes: indoor-outdoor baseline comparison, genera/species identified, accredited lab results, COC documentation. Our written report is formatted specifically to address what Lexington, WA insurance adjusters need for mold damage claim evaluation.