What is Calcium?
Calcium (Ca++) is an electrolyte and a mineral that has a fundamental role in the maintenance of bone strength. Almost 99% of the calcium in our bodies is found in our bones and teeth, but a small fraction is also found in the blood, muscle and other tissue where it plays a vital role in the functioning of the nervous system, the muscular apparatus and the coagulation system.
A large amount of calcium in the blood is bound to proteins and is therefore inactive. The most common protein is the egg-white protein, also called albumin. It is therefore often necessary to take into account the level of albumin in the blood when interpreting calcium values. At Melio, we also offer adjusted calcium, which is a more accurate marker for the amount of active calcium in the blood.
Why is this analysis important?
Many conditions that affect our health and well-being can lead to abnormalities in the level of calcium in the blood. A range of sometimes vague symptoms, such as fatigue, irritability, and tingling sensations can be associated with both too high or too low levels of calcium in the blood. A calcium test is therefore often ordered by doctors as a part of a general health checkup or investigation of suspected bone, kidney, muscle, digestive system as well as certain endocrine or lung problems.
In short, it is useful to analyse calcium levels in the blood to:
Assess dietary calcium intake
Investigate conditions related to calcium metabolism
Monitor the effect of certain medications that can affect blood calcium level
The reference range for calcium levels in the blood can be different depending on the laboratory and technique used. Doctors usually also take into account a number of factors when evaluating calcium values.
High calcium levels in the blood may be associated with:
Overactivity of the parathyroid glands (hyperparathyroidism)
Regular intake of certain medications, such as thiazide-type diuretics, teriparatide, lithium, vitamin A, or theophylline.
Certain lung conditions, such as tuberculosis and sarcoidosis
Certain endocrine conditions, such as adrenal insufficiency, pheochromocytoma and growth hormone excess
Bone-destroying lesions, such as Paget's disease or certain tumors
Excessive bed rest for a long period of time
Low calcium levels in the blood may be associated with:
Low level of calcium in the diet
Malnutrition and low albumin concentration (hypoalbuminemia)
Certain conditions in the digestive system that decrease the absorption of calcium, such as celiac disease, pancreatitis and alcoholism.
Underactivity of the parathyroid glands (hypoparathyroidism)
Bone-forming lesions, such as certain tumors
Intake of certain medications, such as laxatives, Bisphosphonates (eg Zolendronic Acid) or Foscarnet.
Our bodies strive to maintain a relatively constant level of calcium in the blood. If we do not eat enough calcium, our body will take calcium from the bones and give it to the blood to keep the calcium level in the blood stable. This means that a calcium value within the normal range can unfortunately not rule out inadequate calcium intake.
A large amount of calcium in the blood is bound to proteins and is therefore inactive. The most common protein is the egg-white protein, also called albumin. It is therefore often necessary to take into account the level of albumin in the blood when interpreting calcium values.
Tests that include this marker
Etiology of hypocalcemia in adults. David Goltzman, MD. UpToDate Dec 28, 2017
Clinical manifestations of hypocalcemia. David Goltzman, MD. UpToDate Mar 25, 2019
Diagnostic approach to hypercalcemia. Elizabeth Shane, MD. UpToDate Aug 13, 2018
Clinical manifestations of hypercalcemia. Elizabeth Shane, MD UpToDate Apr 03, 2019