Final answer:
For therapeutic drug monitoring, blood samples are typically collected in lavender or purple-colored tubes containing EDTA. From the provided options, yellow can sometimes be used, but it is not standard for EDTA-containing tubes and might vary depending on the lab or test.
Step-by-step explanation:
Most specimens collected for therapeutic drug monitoring require careful handling to ensure that the integrity of the sample is maintained and that the results are accurate. Such specimens are commonly collected in tubes with specific color-coded stoppers, which indicate the type of additive the tube contains to preserve the blood sample or to prepare it for the specific tests being conducted.
The correct tube stopper color for most therapeutic drug monitoring samples is a lavender or purple stopper. These stoppers typically indicate the presence of ethylenediaminetetraacetic acid (EDTA), which is an anticoagulant that helps to preserve the blood sample by chelating calcium and preventing clotting. EDTA tubes, which sometimes may appear pinkish or lavender, ensure that the blood remains in a state suitable for plasma separation and accurate drug level analysis.
From the options provided, though, none directly correspond to an EDTA tube; however, the closest match, which might sometimes be yellow depending on the additional additives or specific testing requirements, would be option 4) Yellow. However, it should be noted that tube colors can vary by manufacturer and the specific test, so it's always best to refer to the lab's collection guide or another trusted source.
The majority of blood samples for drug monitoring are ideally collected in lavender or purple stopper tubes, which contain EDTA as an anticoagulant. If choosing from the listed options without the purple or lavender option, then yellow could be a possibility but is not standard for EDTA.