Serum Calcium Blood Tests and Their Clinical Relevance

Calcium is the most abundant mineral in the body, found in the bones, blood, and other tissues. It helps the body build strong bones and teeth and plays a role in many vital functions such as muscle contractions, nerve transmissions, blood clotting, and hormone production. Calcium also helps to regulate blood pressure and keep the heart beating regularly.


Calcium levels can affect a variety of bodily functions. Low calcium levels, also known as hypocalcemia, can lead to muscle spasms, fatigue, weakness, numbness and tingling in the hands and feet, and confusion. It may also result in osteoporosis. In severe cases, it can lead to seizures and an irregular heartbeat. High calcium levels, or hypercalcemia, can lead to nausea, vomiting, constipation, confusion, and fatigue. It can also cause excessive thirst and frequent urination. High levels of calcium can lead to health problems, such as kidney stones or kidney failure.


Serum Calcium Test


A calcium blood test is used to diagnose and monitor conditions related to calcium levels in the body, bone diseases, and calcium-regulation disorders. Serum calcium is a test that measures the amount of calcium in the blood. It is typically done as part of a routine health exam or if a person has symptoms such as bone pain, muscle weakness, or constipation.


There are two types of calcium blood tests:

  1. Ionized calcium test - Ionized calcium is the active form of calcium in the blood and is the most accurate measure of calcium levels. It can diagnose conditions such as hypercalcemia, hypocalcemia, and other disorders affecting calcium levels, such as kidney disease. Ionized calcium tests measure the concentration of calcium ions in the blood without interference from other substances.


  1. Total calcium test: It measures both ionized calcium and calcium bound to proteins and other substances in the blood, including albumin. Total calcium tests may be used to diagnose hyperparathyroidism, vitamin D deficiency, and other conditions that affect calcium levels.


Procedure for Serum Calcium Blood Tests


During this procedure, a blood sample is drawn from a vein in the arm and sent to a laboratory for analysis. The test measures the amount of calcium in the serum, which is the liquid part of the blood. The results of the serum calcium test are reported in milligrams per deciliter (mg/dL). The normal range for calcium is 8.5 to 10.2 mg/dL. Abnormal calcium levels can indicate a variety of medical problems.


In some cases, the doctor may order additional tests to determine the cause of an abnormal calcium reading. These tests may include a urine test to check for certain hormones that affect calcium levels or a parathyroid hormone test to check for abnormalities in parathyroid gland function.


Clinical Relevance of Calcium Blood Tests


Serum calcium tests are an essential part of a routine health exam. The test measures the amount of calcium in the blood and can help diagnose and treat various medical problems. The most common reason for a doctor to perform a calcium blood test is to check for calcium-related medical conditions.

  • Low calcium levels (hypocalcemia) are often associated with kidney disease, vitamin D deficiency, and certain medications. Hypocalcemia can indicate problems with the parathyroid glands and lead to conditions such as hypoparathyroidism.
  • High calcium levels (Hypercalcemia ) can indicate the presence of kidney disease, certain types of cancer, vitamin D deficiency, or excessive intake of calcium supplements.


A calcium blood test can be used to check for signs of vitamin D deficiency or diagnose certain cancer types. A serum calcium test can also be used to monitor the effectiveness of treatments for conditions such as hyperparathyroidism and kidney disease. In addition, it can be used to monitor calcium levels in people who are taking calcium supplements.


It is crucial to have regular screenings to ensure that calcium levels remain within a healthy range. However, additional tests may be needed to diagnose and treat any underlying conditions if levels are outside of a normal range.


Efficacy and Safety of Calcium Tests


A calcium blood test is a convenient, simple, and non-invasive way to assess a person’s calcium levels and detect any underlying medical conditions. Serum calcium tests are generally considered safe and are not associated with severe side effects.


In most cases, a calcium blood test is done as part of a routine blood workup. It is also sometimes used to monitor calcium levels in people taking calcium supplements or medications that can affect calcium levels. Your doctor may also order a calcium blood test if they suspect you have a condition affecting your calcium levels.


Thus, a calcium blood test is an essential diagnostic tool for ensuring the good overall health and preventing potential complications.

Subscribe To Our Newsletter

Filter out the noise and nurture your inbox with health and wellness advice that's inclusive and rooted in medical expertise.

Subscribe Now   

Medtalks is India's fastest growing Healthcare Learning and Patient Education Platform designed and developed to help doctors and other medical professionals to cater educational and training needs and to discover, discuss and learn the latest and best practices across 100+ medical specialties. Also find India Healthcare Latest Health News & Updates on the India Healthcare at Medtalks