If a blood sample is contaminated with intravenously infused fluids, which analyte is most likely to show an artificial increase?

• A. Glucose (dextrose)
• B. Electrolytes
• C. Drugs
• D. Ammonia

Answer: (A)

Contamination of a blood sample with intravenous fluids changes the measured levels based on what the infusion contains. If the IV fluid includes dextrose (glucose), it adds sugar to the sample, so the glucose measured in the lab will be artificially higher than the patient’s true serum glucose. This happens because the assay reads all the glucose present in the mixture, not distinguishing the patient’s own glucose from the infused solution.

While electrolytes can be altered if the infusion contains electrolytes (for example, saline can raise sodium and chloride), the most consistent and common artificial rise from IV fluids is glucose when dextrose-containing solutions are used. Drugs would only appear elevated if the infusion itself contained those drugs, and ammonia is not typically affected by IV fluid contamination in the same way.