Understanding Serum Calcium
What is Serum Calcium?
A Serum Calcium test measures the level of calcium in the blood. This test detects various health problems associated with the bones, teeth, heart, kidneys, and hormonal imbalances like thyroid disorders or nerve diseases. It is often done as part of routine health checkups.
Calcium is one of the important and abundant minerals in our body. It performs various body functions, such as helping the nerves work properly, cell signaling, and muscle contraction. The body also needs calcium to keep the bones healthy and strong, for blood clotting, and to regulate heart rhythms.
A Serum Calcium test is performed if you experience symptoms such as weakness, fatigue, excessive urination and thirst, nausea, stomach pain, constipation, irregular heartbeat, brittle nails, weak and brittle bones, muscle cramps, irritability, or confusion. This test may also help check the treatment response for abnormal calcium levels and monitor critically ill patients suffering from cancer or kidney disorders. Usually, overnight fasting (8-12 hours) is preferred for this test. Do not eat or drink anything except water before the test.
Test result ranges are approximate and may differ slightly between labs depending on the methodology and laboratory guidelines. Talk to your doctor about your specific test results. Narrate your complete medical history to help them correlate your clinical and laboratory findings and formulate an overall treatment plan.
What is Serum Calcium used for?
A Serum Calcium test is done:
- As part of routine health checkups.
- If you have symptoms of abnormal calcium levels, such as excessive urination and thirst, constipation, irregular heartbeat, brittle nails, weak and brittle bones, muscle cramps, irritability, or confusion.
- To diagnose diseases that may cause calcium abnormalities, such as thyroid and parathyroid disorders, heart diseases, kidney diseases, bone disorders, and dental diseases and disorders that affect how your intestines absorb nutrients like calcium.
- To assess the effectiveness of treatments like calcium and vitamin D supplements in the body.
- To monitor the progress of treatment in conditions associated with the kidneys, heart, bones, thyroid, teeth, and also in certain types of cancers that may affect calcium levels in the body.
- To monitor calcium levels in people during and after blood transfusions or intravenous fluids, in those undergoing major surgery, and in those who have blood protein abnormalities like low albumin.
What does Serum Calcium measure?
A Serum Calcium test measures the levels of calcium in the body. Calcium is the most abundant mineral in the body, and the majority of it is present in the bones and teeth, and the remaining portion (around 1%) is found in the blood. It is normally present in two forms in blood in about equal amounts, namely "bound calcium", which is attached to proteins in the blood, and "free calcium or ionized calcium", which is not attached to any protein.
A Serum Calcium test cannot be used to check for a lack of calcium in your diet or osteoporosis (loss of calcium from bones) as the body can have normal calcium levels even in case of dietary deficiency of calcium. Moreover, the body can normalize mild calcium deficiency by releasing the calcium stored in bones.
Interpreting Serum Calcium results
Normal range: 8.5 to 10.5 mg/dL (2.2 to 2.7 mmol/L approx.)
Hypocalcemia: Below 8.5 mg/dL (Below 2.2 mmol/L approx.)
Hypercalcemia: Above 10.5 mg/dL (Above 2.7 mmol/L approx.)
Calcium concentration in the body is maintained within a narrow normal range between 8.5mg/dL and 10.5mg/dL.
Hypocalcemia or low blood calcium is indicated if calcium concentration lies below the normal range.
Hypercalcemia or high blood calcium is indicated if calcium concentration lies above the normal range.
Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Serum Calcium
Frequently Asked Questions about Serum Calcium
Q. Are there any risks associated with the Serum Calcium test?
Q. What are the signs that indicate you are not getting enough calcium in the body?
Q. Should I take calcium supplements if my test results show low calcium levels?
Q. What is hypocalcemia and its associated symptoms?
Q. What is hypercalcemia and its associated symptoms?
Q. What is osteoporosis, and how is it related to calcium deficiency?
Q. What other tests can be performed if my test results are abnormal?
Q. When can false results appear in the Calcium Test?
- Calcium [Internet]. NIH Office of Dietary Supplements; 06 Oct. 2022 [Accessed 06 Apr. 2023]. Available from: https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/
- Osteoporosis [Internet]. NIA; 15 Nov. 2022 [Accessed 27 Feb. 2023]. Available from: https://www.nia.nih.gov/health/osteoporosis#:~:text=The%20same%20healthy%20lifestyle%20choices,also%20several%20medications%20to%20consider