Which microcollection container should be filled first if collected by capillary puncture?

When performing a capillary puncture, the lavender top container should be filled first because it contains EDTA, which is an anticoagulant. This is important in order to preserve the integrity of the blood sample for hematological studies. EDTA works by binding calcium, which is necessary for blood clotting, thus preventing coagulation of the sample. This allows for accurate testing of blood cells, including complete blood counts.

The order of filling microcollection containers is essential in reducing the risk of cross-contamination of additives that may interfere with test results. Following the lavender top, which is used for hematology tests, the subsequent containers would be filled in a manner that prevents potential contamination from additives present in other tubes, which can significantly affect the analytical results. For instance, the gray top contains additives for glucose preservation, and if filled first, it could introduce glucose into the lavender top and distort the results of tests intended for hematology.

By prioritizing the lavender top container, you ensure that the sample integrity for the hematological analysis remains intact before addressing any additional tests requiring different additives.