Certification of Pharmacy Technicians (ExCPT) Practice Exam

Normal saline solution is?

1. Hypotonic

2. Isotonic

3. Hypertonic

4. Hyperosmotic

The correct answer is: Isotonic

Normal saline solution, which is a sterile solution of sodium chloride (NaCl) in water, is classified as isotonic. This means that its osmolarity is similar to that of the body's own fluids, specifically blood plasma. When isotonic solutions like normal saline are administered, they do not cause a net movement of water into or out of cells, thus maintaining cell volume and preventing cellular swelling (which occurs with hypotonic solutions) or shrinking (which occurs with hypertonic solutions). In a clinical context, normal saline is often used for fluid replacement and as a diluent for medications, ensuring that patients receive fluids that won't disrupt their fluid balance. The isotonic nature of normal saline makes it suitable for many medical applications, including intravenous therapy, without the risk of causing osmotic imbalances.