Medical Terminology: Electrolyte Tests

1. What are Electrolyte Tests?
Electrolytes are salts that are electrically charged ions used to maintain voltage across cell membranes and carry electrical impulses within the body. The concentration of electrolytes within the body is constantly changing. The kidney is the main regulatory organ that adjusts electrolyte levels to maintain a balance. Electrolyte tests are referred to as electrolyte, basic metabolic, or comprehensive metabolic panel. An electrolyte panel measures only electrolytes in a sample of blood. The basic metabolic and comprehensive metabolic panels measure electrolytes and other components.

2. Calcium (Ca) Test
The calcium (Ca) electrolyte test is used to screen for parathyroid gland function, kidney function, kidney stones, pancreatitis, and bone disease. The test also assesses the underlying cause of muscle spasms, depression, confusion, tingling around the mouth and fingers, muscle cramping, and twitching that are caused by low calcium levels in the blood; nausea, vomiting, bone pain, lack of appetite, weakness, abdominal pain, constipation, and increased urination that are caused by a high calcium level in the blood; and abnormal electrocardiogram.

Understanding the Calcium Test
Calcium is required for growth of bones and teeth and for muscle contraction and blood clotting. Nearly all calcium in the body is stored in bone with a minimum amount in blood. Calcium has a homeostatic relationship with phosphate. Calcium increases in blood as phosphate decreases, and calcium decreases when phosphate increases in the blood.
The parathyroid keeps calcium and phosphate balanced. Where there is too much phosphate (too little calcium) in blood, the parathyroid releases the parathyroid hormone (PTH) that stimulates osteoclast, breaking down bone to increase the calcium level in blood. PTH also activates vitamin D to increase absorption of calcium in the gastrointestinal tract. Vitamin D is necessary for calcium absorption and for the kidneys to retain calcium. Too much calcium in the blood causes the thyroid gland to release calcitonin, which moves calcium from blood to bone.
There are two kinds of calcium blood tests that are performed as part of a routine blood screening. The nonionized calcium test measures calcium attached to albumin in the blood. This test is affected by the amount of albumin in the blood. The ionized calcium test measures calcium not attached to albumin in the blood, and therefore is not affected by the amount of albumin in the blood.

3. Magnesium (Mg) Test
The magnesium (Mg) test is used to assess the effects of medication that cause changes in the level of magnesium and for the therapeutic treatment of high and low levels of magnesium. The test is also used to assess the underlying cause of muscle weakness, muscle twitches, muscle irritability, arrhythmia, nausea, vomiting, low blood pressure, and dizziness.

Understanding the Magnesium Test
Magnesium, found mostly in bones and inside cells, is an electrolyte used to transfer potassium and sodium in and out of cells and is used to activate nerves, muscles, and enzymes. The magnesium blood test measures the level of magnesium in a blood sample and is tested along with other electrolytes.

4. Phosphate Test
The phosphate test is used to screen for kidney and bone disease, and to assess parathyroid gland function.

Understanding the Phosphate Test
Phosphorus is a mineral that contains a particle called phosphate, which is necessary for growth of bones and teeth, and for contracting muscles. Most phosphate is in bone. Phosphate and calcium have an inverse relationship. The phosphate test measures the level of phosphate in the blood.

5. Potassium (K) Test
The potassium (K) test is used to screen for cell lysis syndrome, and to assess the effect of total parenteral nutrition (TPN), the adverse effects of diuretics, the effects of kidney dialysis, and the underlying cause of high blood pressure.

Understanding the Potassium Test
Potassium is a mineral stored inside the cell that has multiple functions, including muscle contractions, neural transmission, and fluid balance. Potassium is excreted by the kidneys and regulated by the hormone aldosterone released by the adrenal glands. Potassium and sodium have an inverse relationship. The potassium test measures the level of potassium in blood.

6. Sodium (Na) Test
The sodium (Na) test is used to screen for adrenal gland disease, electrolyte balance, water balance, and kidney disease.

Understanding the Sodium Test
Sodium is a mineral stored outside the cell in blood and lymph fluid that has multiple functions, including muscle contractions, neural transmission, and fluid balance. Sodium is excreted by the kidneys, regulated by the hormone aldosterone, and released by the adrenal glands. Sodium and potassium have an inverse relationship. The sodium test measures the level of sodium in blood.

7. Chloride (Cl) Test
The chloride (Cl) test is administered to assess the underlying cause of metabolic alkalosis, kidney disorder, adrenal gland disorder, confusion, muscle spasms, muscle weakness, and difficulty breathing.

Understanding the Chloride Test
Chloride is an electrolyte found outside the cell and is involved in fluid balance. The chloride test measures the level of chloride in blood.

Basic Questions
Electrolyte Tests

1. What are electrolytes?
Electrolytes are salts that are electrically charged ions used to maintain voltage across cell membranes and carry electrical impulses within the body.

2. What organ adjusts electrolytes?
The kidney makes adjustments to keep electrolytes in balance.

3. What are other names for electrolyte tests?
Electrolyte tests are referred to as electrolyte, basic metabolic, or comprehensive metabolic panels.

4. What is measured by an electrolyte panel?
An electrolyte panel measures only electrolytes in a sample of blood.

5. What is measured by a basic metabolic panel and a comprehensive metabolic panel?
The basic metabolic and comprehensive metabolic panels measure electrolytes and other components.

6. Why would the calcium test be ordered?
The calcium electrolyte test is used to screen for parathyroid gland function, kidney function, kidney stones, pancreatitis, and bone disease. The test also assesses the underlying cause of muscle spasms, depression, confusion, tingling around the mouth and fingers, muscle cramping, and twitching that are caused by low calcium levels in the blood; nausea, vomiting, bone pain, lack of appetite, weakness, abdominal pain, constipation, and increased urination that are caused by a high calcium level in the blood; and abnormal electrocardiogram.

7. Calcium has a homeostatic relationship with what other electrolyte?
Calcium has a homeostatic relationship with phosphate.

8. What keeps calcium and phosphate in balance?
Parathyroid keeps calcium and phosphate in balance.

9. What removes calcium from blood to bone?
Too much calcium in the blood causes the thyroid gland to release calcitonin, which moves calcium from blood to bone.

10. What is the ionized calcium test?
The ionized calcium test measures calcium not attached to albumin in the blood and therefore is not affected by the amount of albumin in the blood.

11. What is the nonionized calcium test?
The nonionized calcium test measures calcium attached to albumin in the blood. This test is affected by the amount of albumin in the blood.

12. Why might the health care provider order a magnesium test?
The magnesium test is used to assess the effects of medication that causes changes in the level of magnesium and helps determine the therapeutic treatment of high and low levels of magnesium. The test is also used to assess the underlying cause of muscle weakness, muscle twitches, muscle irritability, arrhythmia, nausea, vomiting, low blood pressure, and dizziness.

13. What is the function of magnesium?
Magnesium, found mostly in bones and inside cells, is an electrolyte and is used to transfer potassium and sodium in and out of cells. It is used to activate nerves, muscles, and enzymes.

14. What is the purpose of administering the phosphate test?
The test is used to screen for kidney and bone disease, and to assess parathyroid gland function.

15. What is the function of phosphate?
Phosphate is necessary for growth of bones and teeth and for contracting muscles.

16. What is the difference between phosphate and phosphorus?
Phosphorus is a mineral that contains a particle called phosphate.

17. Why is the potassium test ordered?
The potassium test is used to screen for cell lysis syndrome and assess the effect of total parenteral nutrition (TPN) and kidney dialysis, the adverse effect of diuretics, and to assess the underlying cause of high blood pressure.

18. Where is potassium stored in the body?
Potassium is a mineral stored inside the cell.

19. What is the function of potassium?
Potassium has multiple functions including muscle contractions, neural transmission, and fluid balance.

20. What regulates potassium?
Potassium is regulated by the hormone aldosterone released by the adrenal glands.

21. By what organ is potassium excreted?
Potassium is excreted by the kidneys.

22. What electrolyte has an inverse relationship with potassium?
Potassium and sodium have an inverse relationship.

23. Why is the sodium test ordered?
The sodium test is used to screen for adrenal gland disease, electrolyte balance, water balance, and kidney disease.

24. Where is sodium located in the body?
Sodium is a mineral stored outside the cell in blood and lymph fluid.

25. What is the function of sodium in the body?
Sodium has multiple functions including muscle contractions, neural transmission, and fluid balance.