In a standard phlebotomy draw where multiple tests are ordered, which specimen is typically drawn first to minimize contamination?

In a standard phlebotomy draw where multiple tests are ordered, which specimen is typically drawn first to minimize contamination?

• A. CBC
• B. Blood Culture
• C. PT
• D. WBC

Answer: (B)

The main idea is that the blood culture specimen must be drawn first to prevent contamination of the culture results. Blood cultures are used to detect bacteria in the bloodstream, and they are especially susceptible to being contaminated by skin flora or by residues from subsequent tubes. By collecting the culture first, with strict sterile technique and allowing the antiseptic to dry, you minimize the chance that organisms from the skin or from additives in later tubes will enter the culture bottle. Once the culture is obtained, the remaining tubes (which use different additives for hematology or chemistry tests) can be drawn in the usual sequence without risking interference with the culture result.

The main idea is that the blood culture specimen must be drawn first to prevent contamination of the culture results. Blood cultures are used to detect bacteria in the bloodstream, and they are especially susceptible to being contaminated by skin flora or by residues from subsequent tubes. By collecting the culture first, with strict sterile technique and allowing the antiseptic to dry, you minimize the chance that organisms from the skin or from additives in later tubes will enter the culture bottle. Once the culture is obtained, the remaining tubes (which use different additives for hematology or chemistry tests) can be drawn in the usual sequence without risking interference with the culture result.