What is the consequence of dehydration on laboratory results?

Dehydration has significant effects on laboratory results, particularly due to the concentration of analytes in the blood. When a patient is dehydrated, there is a reduction in plasma volume, which leads to hemoconcentration. This means that the concentrations of certain substances, such as electrolytes, enzymes, and metabolites in the blood, can appear falsely elevated when tested.

For example, if a blood sample is drawn from a dehydrated person, the proportion of red blood cells to plasma is increased, which can skew results. Consequently, tests for sodium, potassium, and other markers may show values higher than they genuinely are because the fluid component of the blood is reduced. Additionally, dehydration can affect various biochemical parameters by causing the kidneys to conserve water, which further concentrates materials in the blood.

In contrast, hydration or proper fluid balance generally results in more accurate and representative laboratory values since the components in the blood are diluted to normal levels. Therefore, dehydration is crucial to consider when interpreting laboratory results, as it can lead to potential misdiagnosis or mismanagement based on inaccurately elevated values.