Impact of blood volume, air exposure duration, transport duration, and testing delay on plasma total carbon dioxide in simulated open collections using microtainers

Plasma TCO₂ decreased with reduced microtainer blood volume, extended off-site transport duration of centrifuged whole blood and testing delay of aliquoted plasma. To minimize TCO₂ reduction, microtainers should be fully filled and tested rapidly. Laboratories should also consider whether an interpretive comment, correction factor or separate reference intervals are appropriate for these tests.