Which specimen type is explicitly noted as not prepared due to contamination?

• A. Nail clippings (not prepared due to contamination)
• B. Urine sample
• C. Sweat sample
• D. Oral fluid sample

Answer: (A)

Contamination can render a specimen unusable for accurate analysis, so labs will sometimes flag it as not prepared. Here, the note “not prepared due to contamination” is attached to nail clippings, signaling that this specimen type was explicitly deemed unsuitable for processing because of contamination. Nail clippings are particularly prone to surface contamination from handling, cosmetics, or environmental substances, which can compromise drug testing results, so this explicit warning makes them the best answer. The other specimen types are not described with an explicit precluding note in this stem, so they aren’t indicated as not prepared for contamination in this context.