American Medical Technologist (AMT) Practice Exam

If contamination occurs from an EDTA evacuated tube, which test could be adversely affected?

1. Sodium level

2. Potassium level

3. Blood glucose level

4. Calcium level

The correct answer is: Potassium level

When considering the potential effects of contamination from an EDTA evacuated tube, the potassium level is particularly sensitive. EDTA is an anticoagulant commonly used in blood collection tubes for hematology tests, but it can also interfere with certain biochemical tests within the blood sample. The potassium level can be adversely affected because EDTA can cause hemolysis, which leads to the release of potassium from the cells into the serum or plasma. If EDTA contaminates a sample, it may skew potassium measurements, leading to falsely elevated levels. This is important in clinical practice as accurate potassium levels are critical for diagnosing and managing conditions related to electrolyte imbalances, such as kidney function and cardiac health. In contrast, while sodium, glucose, and calcium levels can also be impacted by contamination or improper handling, they are generally less influenced directly by EDTA contamination in the same way that potassium levels are. Sodium levels can be altered but are less frequently affected by EDTA directly. Blood glucose is affected mainly by metabolic activity post-collection rather than by EDTA. Calcium can be affected by various factors, but the specific interference from EDTA primarily increases the potential for inaccuracies in potassium measurements.