Which of the following tubes should the phlebotomist draw first for a capillary collection?

Lithium heparin, like other anticoagulants, can influence test results by altering blood chemistry parameters. Drawing this tube before the EDTA tube could lead to unintended mixing of additives, potentially affecting subsequent analyses. To maintain sample integrity and prevent additive interactions, the phlebotomist should prioritize collecting the EDTA tube first.

Nonadditive tubes are used for serum collection rather than capillary blood sampling. These tubes lack any anticoagulant or clot activator, making them unsuitable for capillary blood collection procedures. Therefore, drawing a nonadditive tube first in this context would be incorrect and incompatible with capillary sampling requirements.

Sodium fluoride acts as an antiglycolytic agent to preserve glucose levels in blood samples for glucose testing. While important for certain analyses, such as glucose measurements, drawing the sodium fluoride tube before the EDTA tube in capillary collection could introduce fluoride into the sample, potentially affecting coagulation studies or other tests sensitive to anticoagulant interference.