Sodium
This test is not available separately but included in several packages and available as an addition to an investigation.
Sodium is a salt and is also called an electrolyte because it has a positive charge (Na+). The sodium in the blood is mainly determined to assess dehydration and fluid balance problems. Usually this test is requested together with other salts like potassium. The kidneys play an important role in fluid balance and therefore the kidney function is often determined.