Canadian Society for Medical Laboratory Science (CSMLS) Practice Exam

What is a common result of a hemolyzed serum specimen?

1. Elevated potassium

2. Elevated LDH

3. Decreased glucose

4. Elevated blood urea nitrogen

The correct answer is: Elevated potassium

In a hemolyzed serum specimen, red blood cells are disrupted, leading to the release of intracellular contents into the serum. One of the primary components released is potassium. The elevated potassium (hyperkalemia) observed in hemolyzed samples can significantly affect test results, making it a common finding in such specimens. Hemolysis causes the disruption of the cell membrane of red blood cells, which releases intracellular components, including hemoglobin and potassium, into the serum. If a specimen is hemolyzed, it can easily lead to falsely elevated potassium levels, which is a critical consideration for lab results. While lactate dehydrogenase (LDH) can also be elevated due to hemolysis, the context of potassium being released specifically from red blood cells is a more characteristic and immediate result. Additionally, glucose levels might decrease in severely hemolyzed samples due to the metabolic activity of the released cells, but this is less common compared to the marked increase in potassium. Elevated blood urea nitrogen (BUN) is not directly related to hemolysis and is not typically used as a marker for evaluating hemolyzed samples.