What is the normal range for potassium (K+) levels in mEq/L?

The normal range for potassium (K+) levels in mEq/L is considered to be between 3.5 and 4.5. This range is crucial because potassium is an essential electrolyte that plays a vital role in various physiological functions, including muscle contraction, nerve transmission, and maintaining fluid balance.

Maintaining potassium levels within this range is important for heart function, as both low and high potassium levels can lead to serious cardiac complications. For instance, hypokalemia, which occurs when potassium levels drop below the normal range, can cause muscle weakness, cramping, and irregular heart rhythms. Conversely, hyperkalemia, which refers to excessive levels of potassium, can also result in dangerous heart arrhythmias.

The other ranges provided do not align with the widely accepted normal potassium levels. For example, levels below 3.5 indicate a potential deficiency, while levels above 4.5 may suggest excess potassium, both of which would require further evaluation and management. Thus, the selection of the range 3.5 to 4.5 reflects standard medical practice concerning potassium homeostasis.