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

A hemolyzed blood sample can significantly elevate levels of which of the following?

1. Sodium, calcium, chlorine

2. Potassium, iron, magnesium

3. Calcium, magnesium, phosphate

4. Iron, sodium, protein

The correct answer is: Potassium, iron, magnesium

A hemolyzed blood sample can significantly elevate levels of potassium, iron, and magnesium due to the release of intracellular contents from hemolyzed red blood cells into the plasma. When red blood cells undergo hemolysis, they break open, releasing potassium into the serum, often leading to a marked increase in measured potassium levels. This can be particularly significant since potassium is normally found at much higher concentrations inside cells than in the plasma, thus a hemolyzed sample may not accurately reflect the patient's actual serum potassium level. Iron is also released from hemolyzed cells, specifically from hemoglobin, which can contribute to elevated serum iron levels in a hemolytic sample. This reflects the breakdown and release of heme, which is subsequently converted into free iron. Magnesium levels can also be influenced as it is present in both the serum and inside red blood cells. While magnesium typically does not shift as dramatically as potassium, hemolysis can lead to some elevation in the serum magnesium concentration. In contrast, other options involve levels that may not show a consistent or significant increase due to hemolysis. For instance, sodium and chloride levels are generally stable and are not significantly affected by hemolysis, as these are primarily extracellular electrolytes.