What is the most likely cause of pseudohyponatremia in a patient with significantly high triglycerides?

Pseudohyponatremia occurs when the measured serum sodium concentration appears low due to the presence of an increased volume of non-aqueous components in the serum, particularly lipids or proteins, which can displace water content. In the context of a patient with significantly high triglycerides, lipemia can cause in vitro interference during the measurement of sodium levels.

When triglycerides are elevated, they can cause a dilutional effect, leading to falsely low sodium readings. This type of interference is particularly noted in patients with severe hyperlipidemia because the lipids can alter the way sodium is measured by various laboratory assays, particularly those that rely on the theory that sodium is measured in a specific aqueous environment.

In contrast, hemolysis would typically lead to the release of intracellular components that can skew electrolyte measurements differently. Serum separation issues could lead to problems but are less directly tied to the effect seen with high triglycerides. Contamination of the sample does not pertain to the presence of high triglycerides and would not specifically relate to the condition of pseudohyponatremia associated with lipid presence.

Understanding the interference caused by lipemia is critical for laboratory interpretation, especially in cases where hyperlipidemia is present, as it leads to