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Mold Testing: Modern Strategies (Part 2)

Part 2: Advanced Mold Sampling Methods – ERMI and HERTSMI-2 Testing

In the previous blog post, we discussed direct sampling and air sampling methods for assessing mold in indoor environments. In this second part, we will explore two advanced mold sampling methods: ERMI (Environmental Relative Moldiness Index) and HERTSMI-2 (Health Effects Roster for Stachybotrys Mycotoxins).

ERMI Testing:

ERMI testing is a relatively recent advancement in mold sampling. It was developed by the U.S. Environmental Protection Agency (EPA) to provide a more comprehensive evaluation of indoor mold. ERMI combines DNA-based analysis and data on specific mold species to create an index that quantifies the relative moldiness of an environment.

HERTSMI-2 Testing:

HERTSMI-2 testing, on the other hand, is designed specifically to detect the presence of mycotoxins, which are toxic substances produced by certain molds, such as Stachybotrys. These mycotoxins can have severe health effects.

In part 3 of this series, we will walk you through the things to think about when trying to decide which test is best for you.

Benefits of ERMI Testing:

  1. Quantitative Assessment: ERMI provides a quantitative measurement of mold contamination, making it easier to compare different locations or assess changes over time.
  2. Identification of Water Damage: It identifies mold species associated with water damage, helping to identify the source of moisture problems.

Deficiencies of ERMI Testing:

  1. Cost: ERMI testing can be more expensive than traditional methods, which may not be necessary for routine assessments.
  2. Complex Interpretation: Interpreting ERMI results requires a good understanding of mold species and their health implications, which can be challenging for the average person.

Benefits of HERTSMI-2 Testing:

  1. Targeted Mycotoxin Detection: It specifically detects mycotoxins, offering insight into potential health risks associated with certain molds.
  2. Health Risk Assessment: Identifying mycotoxins helps assess the potential health risks for individuals in the environment.

Deficiencies of HERTSMI-2 Testing:

  1. Limited Scope: HERTSMI-2 focuses on mycotoxins, but it may not provide a complete picture of the overall mold contamination in the environment.
  2. Cost: Like ERMI, HERTSMI-2 testing can be costly, and it may not be necessary for routine assessments.

Jump To Part 1: History

Jump To Part 3: Decision Tree

** EPA Mold Resources



Committed to Your Safety and Peace of Mind – Jennifer Thorne Testing Services Manager  | IAC2 Certified for Mold & Radon | NRPP Certified: 113525-RMP, 113629-RMS | DEQ Meth Certified: MCP-0146-C