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Dr. Nitika Vashisht
MD Pathology, MBBS
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Serum Calcium

Also known as Calcium blood test, S. Calcium, Serum Ca
You need to provide
This test is for
Male, Female
Test Preparation
  1. Overnight fasting is preferred but not mandatory.

Understanding Serum Calcium

What is Serum Calcium?

A Serum Calcium test, also known as a calcium blood test, measures the calcium level in the blood. Serum calcium levels are vital for various bodily functions, including maintaining strong bones and teeth, regulating muscle contractions (including the heart), transmitting nerve signals, and ensuring effective blood clotting. It is often done as part of routine health checkups.

Calcium is one of the important and abundant minerals in our body. It is essential for various bodily functions, such as nerve transmission, 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 weakness, fatigue, excessive urination and thirst, nausea, stomach pain, constipation, irregular heartbeat, brittle nails, weak and brittle bones, muscle cramps, irritability, or confusion. Furthermore, a calcium blood test aids in the diagnosis of conditions related to calcium metabolism, parathyroid disorders, kidney diseases, and bone health. 

Regular calcium testing may also help monitor the treatment response for abnormal calcium levels, especially in critically ill patients like those suffering from cancer or kidney disorders. It is particularly crucial for individuals with chronic conditions to ensure optimal health.

Low calcium levels, known as hypocalcemia, can be linked to causes such as hypoparathyroidism, kidney diseases, malabsorption disorders, or vitamin D deficiency. On the other hand, high calcium levels, termed hypercalcemia, can be associated with symptoms signaling hyperparathyroidism, certain cancers, kidney dysfunction, or excessive calcium supplementation.

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. These will help the doctor determine appropriate treatments, whether through calcium supplements, medications, dietary adjustments, or lifestyle modifications.

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 treatment progress in conditions associated with the kidneys, heart, bones, thyroid, teeth, and 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, those undergoing major surgery, and those with 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; most of it is present in the bones and teeth, and the remaining portion (around 1%) is found in the blood. It is usually present in two forms in blood in about equal amounts: "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 lack of calcium in your diet or osteoporosis (loss of calcium from bones) as the body can have normal calcium levels even in dietary calcium deficiency. 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 a Serum Calcium test?

There is usually no risk associated with this test. However, some people may feel a slight sting while the needle is pricked and may experience some bleeding that is normal and usually not bothersome. Some people may experience slight swelling or bruising at the site of the needle prick. Applying ice 3-4 times daily for about a week may help reduce swelling and bruising. If it does not get better, consult your doctor.

Q. What are the signs that indicate you are not getting enough calcium in the body?

Brittle nails, tooth troubles, sleep problems, numbness and tingling in hands and feet, and muscle cramps are some of the signs that you are not getting enough calcium.

Q. Should I take calcium supplements if my test results show low calcium levels?

Always consult your doctor before taking calcium supplements. However, a healthy diet including milk, cheese, yogurt, green leafy vegetables, and almonds can support your daily calcium needs.

Q. What is hypocalcemia and its associated symptoms?

Hypocalcemia is a condition where the blood calcium levels are below the normal range. Symptoms associated with hypocalcemia include weak and brittle hairs, brittle nails, thin and brittle bones that fracture easily, numbness and tingling sensation, muscle spasms and cramps, confusion, memory loss, hallucinations, and seizures.

Q. What is hypercalcemia and its associated symptoms?

Hypercalcemia is a condition where blood calcium levels are higher than the normal range. The symptoms associated with hypercalcemia include headache, weakness, fatigue, excessive urination and thirst, nausea, stomach pain, constipation, irregular heartbeat, weak and brittle bones, muscle cramps, irritability, confusion, and coma, which can be potentially fatal.

Q. What is osteoporosis, and how is it related to calcium deficiency?

Bones are the primary reservoirs of calcium in our body. The body needs a constant level of calcium for the functioning of various parts, such as the heart, muscles, and nerves. When these body parts need calcium, they take it from the calcium stored in the bones. Over time, when the body depletes calcium stores in the bones, it leads to osteoporosis, characterized by fragile bones and an increased risk of falling.

Q. What other tests can be performed if my test results are abnormal?

Other tests that may be performed if your test results are abnormal include an ionized calcium test, urine calcium test, vitamin D test, electrolyte panel test, kidney function test, parathyroid hormone (PTH) test, PTH-related peptide test (PTHrH), and electrocardiography (ECG).

Q. What is the difference between a Serum Calcium test and a Calcium Score test?

A Serum Calcium test is a blood test that analyzes the amount of calcium in your blood, whereas a Calcium Score test is a CT scan that checks how much calcium is in your coronary arteries since this score can indicate if there is plaque accumulation in your arteries, which can narrow or block them.

Q. When can false results appear in a Serum Calcium test?

False results may appear in newborns, showing hypocalcemia. This is usually due to the immature parathyroid gland. False results may also appear after a large volume of blood transfusion. Additionally, some medications can elevate or lower blood calcium levels.
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Serum Calcium test price for other cities

Price inBangaloreRs. 199
Price inKolkataRs. 199
Price inMumbaiRs. 199
Price inPuneRs. 199
Price inHyderabadRs. 199
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