Why discard the first drop of blood in a skin puncture?

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Multiple Choice

Why discard the first drop of blood in a skin puncture?

In capillary blood collection, the first drop is discarded to remove tissue fluid from the puncture site. That initial drop can be contaminated with interstitial fluid and surface contaminants as the puncture heals and blood begins to flow, which can dilute the blood or alter the concentration of analytes. By removing that drop, the subsequent drop provides a more representative sample of true capillary blood, improving the accuracy of test results. This practice isn’t about dead skin cells, it doesn’t make the blood flow easier, and it doesn’t aim to increase volume; it’s about avoiding contamination from tissue fluid.

In capillary blood collection, the first drop is discarded to remove tissue fluid from the puncture site. That initial drop can be contaminated with interstitial fluid and surface contaminants as the puncture heals and blood begins to flow, which can dilute the blood or alter the concentration of analytes. By removing that drop, the subsequent drop provides a more representative sample of true capillary blood, improving the accuracy of test results. This practice isn’t about dead skin cells, it doesn’t make the blood flow easier, and it doesn’t aim to increase volume; it’s about avoiding contamination from tissue fluid.

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