Blank samples serve two purposes in practice; they indicate whether the media is contaminated and whether the sampling technique was poor.

Blank samples serve two purposes in practice; they indicate whether the media is contaminated and whether the sampling technique was poor.

• A. They indicate contamination of the sampling media
• B. They indicate both media contamination and sampling technique quality
• C. They indicate improvement areas for field staff
• D. They indicate nothing about sampling quality

Answer: (B)

Blank samples are used to check the integrity of both the sampling media and the way the sampling is performed. They go through the same handling and processing steps as real samples but contain no source material, so any contaminants that appear come from the media or from the sampling process itself. If a blank shows contamination, it flags problems with the media or with the field procedures, indicating that the sampling technique might have introduced contaminants. This dual function—detecting media contamination and assessing whether the sampling method was performed correctly—explains why blank samples serve two purposes. They don’t simply indicate media contamination, nor are they only about staff performance, and they do provide information about sampling quality.

Blank samples are used to check the integrity of both the sampling media and the way the sampling is performed. They go through the same handling and processing steps as real samples but contain no source material, so any contaminants that appear come from the media or from the sampling process itself. If a blank shows contamination, it flags problems with the media or with the field procedures, indicating that the sampling technique might have introduced contaminants. This dual function—detecting media contamination and assessing whether the sampling method was performed correctly—explains why blank samples serve two purposes. They don’t simply indicate media contamination, nor are they only about staff performance, and they do provide information about sampling quality.