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Updated: Aug 20, 2026
Collection and Extraction of Occupational Air Samples for Analysis of Fungal DNA
Published on: May 2, 2018
[Comparison of mycological and chemical analytical laboratory methods for detecting mold damage in indoor
D Laussmann1, D Eis, H Schleibinger
1Robert Koch-Institut, Berlin. LaussmannD@rki.de
Abstract:
To evaluate frequently used methods that discriminate between moldy and nonmoldy indoor environments, 45 homes with visible mold growth and 47 definitively non-infested homes, both confirmed by inspection, were investigated by microbiological and chemical analytical methods. The study was laboratory blinded in relation to the confirmed mold status of the rooms. Statistical evaluation of the results of the applied mycological methods with the Receiver Operating Characteristic (ROC) curve analysis showed that these methods (impaction, open Petri dish method, and determination of mold spores in house dust samples) performed very well in discriminating between rooms with visible mold growth and nonmoldy rooms when the sum score of the mold genera Aspergillus and Penicillium was used as an indicator. The calculated areas under the ROC curves (AUC) of the three mycological methods were: 0.992 (95% CI 0.942-0.997) for mold spores in house dust samples, 0.996 (95% CI 0.940-0.998) for the open Petri dish method, and 0.999 (95% CI 0.957-1.000) for the determination of airborne spores with the Andersen impactor, respectively. A perfect discrimination would lead to an AUC of 1. These results were obtained with DG 18-agar as well as with malt extract agar. In contrast to the results of the mycological methods, the chemical analytical method under the same study conditions showed a distinctly lower performance in discriminating rooms according to their mold status when a sum score (concentration of eight typical MVOC) was used as an indicator. The area under the ROC curve (AUC) had a value of 0.620 (95% CI 0.509-0.723). A completely useless test would have an AUC of 0.5. As the lower limit of the 95% confidence interval of the area under the ROC curve is close to 0.5, the results obtained with the MVOC method do not differ from the classification results which can be obtained simply by chance. Possible methodological biases which could have lead to this interpretation are discussed.
Insights
Mycological methods accurately distinguish moldy from non-moldy indoor environments. Chemical analysis of mold-specific volatile organic compounds (MVOCs) showed poor discrimination, similar to chance.
Area of Science:
- Environmental Science
- Microbiology
- Indoor Air Quality
Background:
- Differentiating between mold-contaminated and mold-free indoor spaces is crucial for public health.
- Reliable methods are needed to assess indoor environments for mold presence.
Purpose of the Study:
- To evaluate the effectiveness of common microbiological and chemical methods in distinguishing moldy from non-moldy indoor environments.
- To compare the discriminatory power of mycological techniques versus chemical analysis of mold-specific volatile organic compounds (MVOCs).
Main Methods:
- Investigated 45 mold-infested and 47 non-infested homes using laboratory-blinded microbiological (impaction, open Petri dish, dust analysis) and chemical (MVOC concentration) methods.
- Applied Receiver Operating Characteristic (ROC) curve analysis to statistically evaluate the performance of each method.
- Utilized DG 18-agar and malt extract agar for mycological analyses.
Main Results:
- Mycological methods demonstrated excellent discrimination between moldy and non-moldy rooms, with Areas Under the ROC Curve (AUC) ranging from 0.992 to 0.999.
- The sum score of Aspergillus and Penicillium genera was a highly effective indicator in mycological assessments.
- Chemical analysis of eight MVOCs showed significantly lower performance (AUC = 0.620), with results not reliably differing from chance.
Conclusions:
- Mycological methods, particularly analyzing mold spores in dust and airborne spores, are highly effective for identifying moldy indoor environments.
- Chemical analysis of MVOCs is currently unreliable for discriminating between moldy and non-moldy indoor spaces.
- Further investigation into potential methodological biases affecting MVOC analysis is warranted.
