Adj. Calcium

Overview

Adjusted calcium is a calculation used to account for the influence of albumin, a protein in the blood that binds to calcium. Total calcium levels measured in routine blood tests include both ionized calcium (the active form that affects nerve and muscle function) and calcium bound to proteins like albumin. Changes in albumin levels can alter the amount of calcium bound to it, leading to variations in total calcium readings. Adjusted calcium corrects for these variations by estimating what the total calcium level would be if the albumin level were within the normal range.

Testing Levels:

• High (2.6 mmol/L) - When adjusted calcium levels are elevated, it usually signifies an increase in the active form of calcium in the bloodstream, known as ionized calcium. This rise can be attributed to several underlying factors. Hyperparathyroidism is a condition where the parathyroid glands produce excessive parathyroid hormone (PTH), which regulates calcium levels. Elevated PTH levels can prompt excessive calcium release from bones and increased absorption from the intestines, leading to higher blood calcium levels. Similarly, hypercalcemia of malignancy can occur in certain cancers, such as those affecting the bones or glands like the parathyroid or lungs. These cancers may produce substances that mimic PTH or directly release calcium into the bloodstream, contributing to elevated calcium levels.
  
  Additionally, excessive intake or production of vitamin D can enhance calcium absorption from the intestines, potentially resulting in hypercalcemia. Kidney disorders, including chronic kidney disease or kidney stones, might impair calcium excretion, allowing calcium levels in the blood to increase. Certain medications, such as thiazide diuretics, lithium, and calcium supplements, are known to elevate blood calcium levels.
  
  
• Mid - When adjusted calcium levels fall within the normal range, it signifies a state where the active form of calcium in the bloodstream, known as ionized calcium, is balanced and adequate for physiological needs. This balance is crucial for various bodily functions, including muscle contraction, nerve transmission, blood clotting, and maintaining healthy bones.
  
  Normal adjusted calcium levels are maintained through a complex interplay of factors. Calcium absorption from the intestines, facilitated by vitamin D, plays a key role in ensuring adequate calcium levels in the blood. Calcium is also released from bones under the influence of parathyroid hormone (PTH), which responds to changes in blood calcium levels. Additionally, the kidneys regulate calcium balance by either reabsorbing calcium to maintain levels or excreting excess calcium as needed.
  
  
• Low (2.1 mmol/L) - When adjusted calcium levels are low, it usually indicates a decrease in the active form of calcium in the bloodstream, known as ionized calcium. This reduction can occur due to various underlying factors. Hypoparathyroidism is a condition where the parathyroid glands produce insufficient parathyroid hormone (PTH), which normally helps regulate calcium levels by stimulating calcium release from bones and absorption from the intestines. Low PTH levels result in diminished calcium levels in the blood.
  
  Vitamin D deficiency is another common cause of low adjusted calcium levels. Inadequate intake of vitamin D or impaired activation of vitamin D in the body hinders calcium absorption from the intestines, leading to decreased blood calcium levels. Additionally, conditions such as hypomagnesemia (low magnesium levels) can impair PTH secretion and action, indirectly contributing to lower calcium levels. Kidney disease, particularly chronic kidney disease or other disorders affecting kidney function, can impair the kidneys' ability to retain calcium, resulting in increased calcium loss through urine and further lowering blood calcium levels. Certain medications, such as antiepileptic drugs and bisphosphonates, can also lower blood calcium levels as a side effect.

Why We Test Adj. Calcium

What Affects It

Adjusted calcium levels in the body can be influenced by several factors. They are calculated based on total calcium and albumin levels in the blood, so changes in albumin levels can affect adjusted calcium readings. Acid-base imbalances, kidney function, and disorders affecting parathyroid hormone (PTH) secretion can also impact calcium balance and adjusted calcium levels. Additionally, vitamin D levels, medications like diuretics and corticosteroids, and various health conditions such as bone disorders and gastrointestinal diseases can all contribute to fluctuations in adjusted calcium levels. Monitoring adjusted calcium levels helps healthcare providers assess calcium metabolism, diagnose conditions like hypercalcemia or hypocalcemia, and manage overall health effectively.

How to Improve

Common Name: Adj. Calcium