American Society for Clinical Pathology (ASCP) Histotechnician Certification Practice Exam

The correct specimen to collect in an anticoagulant tube and place in ice water is for lactate levels. Lactate testing is crucial in clinical settings, particularly for evaluating lactic acidosis, and it is sensitive to temperature changes. The metabolic production of lactate can be increased at elevated temperatures, which can lead to falsely elevated results if the sample is not promptly processed or kept at controlled temperatures.

By using an anticoagulant tube, the blood sample is preserved in its liquid state and prevents coagulation, allowing for accurate measurement of lactate levels. Placing the sample in ice water halts metabolic processes and reduces the risk of further lactate production.

While sodium, glucose, and calcium levels are also important lab tests, they do not require the same immediate cooling and handling procedures to ensure accuracy like lactate levels do. For example, glucose does require timely processing but does not necessitate ice water; its stability is maintained under room temperature conditions for a short duration.