When should a lavender top tube be drawn for a CBC?

When should a lavender top tube be drawn for a CBC?

• A. Before a light blue tube
• B. After a light blue tube
• C. At any time during the draw
• D. Only when specified by a doctor

Answer: (B)

The lavender top tube should be drawn after a light blue tube because of the order of draw protocols established to prevent contamination of the sample. The light blue tube is used for coagulation studies, which require a specific additive (sodium citrate) that can affect the results of tests performed on other tubes if not drawn in the correct order. Drawing the lavender tube, which is typically used for a complete blood count (CBC) containing EDTA as an anticoagulant, after the light blue tube ensures that any potential contamination from the coagulant in the light blue tube is eliminated. This maintains the integrity of the CBC results, allowing them to be as accurate as possible. The correct sequence of drawing blood tubes is crucial in phlebotomy, as it helps maintain the validity of the test results and avoids any errors that could arise from improper handling of the samples.

The lavender top tube should be drawn after a light blue tube because of the order of draw protocols established to prevent contamination of the sample. The light blue tube is used for coagulation studies, which require a specific additive (sodium citrate) that can affect the results of tests performed on other tubes if not drawn in the correct order. Drawing the lavender tube, which is typically used for a complete blood count (CBC) containing EDTA as an anticoagulant, after the light blue tube ensures that any potential contamination from the coagulant in the light blue tube is eliminated. This maintains the integrity of the CBC results, allowing them to be as accurate as possible.

The correct sequence of drawing blood tubes is crucial in phlebotomy, as it helps maintain the validity of the test results and avoids any errors that could arise from improper handling of the samples.