From the Guidelines
To evaluate hypocalcemia, order the following labs: serum calcium, ionized calcium, parathyroid hormone (PTH), magnesium, and creatinine concentrations, as these tests provide a comprehensive assessment of calcium metabolism and help identify the underlying cause of hypocalcemia. When evaluating hypocalcemia, it is essential to consider the patient's clinical presentation and medical history. The labs indicated for hypocalcemia include:
- Serum calcium: measures total calcium levels
- Ionized calcium: reflects the biologically active form of calcium
- Parathyroid hormone (PTH): helps evaluate parathyroid function, which is crucial for calcium regulation
- Magnesium: an important electrolyte that interacts with calcium homeostasis
- Creatinine concentrations: helps assess renal function, which can impact calcium metabolism These tests should be ordered in conjunction with a thorough clinical evaluation, including assessment of symptoms such as fatigue, emotional irritability, and abnormal involuntary movements, as well as consideration of potential underlying causes, such as hypoparathyroidism, hypothyroidism, and hypomagnesemia 1. Regular monitoring of calcium concentrations should be considered at vulnerable times, such as peri-operatively, perinatally, or during severe illness, to prevent complications associated with hypocalcemia, including cardiac arrhythmias and osteopenia/osteoporosis 1. It is also important to note that treatment of hypocalcemia should be individualized and may involve calcium and vitamin D supplementation, as well as consultation with an endocrinologist for more severe cases 1.
From the FDA Drug Label
In children, the creatinine clearance value must be corrected for a surface area of 1. 73 square meters. A serum iPTH level of ≥ 100 pg/mL is strongly suggestive of secondary hyperparathyroidism. Dialysis Patients Calcitriol is indicated in the management of hypocalcemia and the resultant metabolic bone disease in patients undergoing chronic renal dialysis Hypoparathydroidism Patients Calcitriol is also indicated in the management of hypocalcemia and its clinical manifestations in patients with postsurgical hypoparathyroidism, idiopathic hypoparathyroidism, and pseudohypoparathyroidism.
The labs indicated for hypocalcemia are:
- Serum iPTH level: to assess for secondary hyperparathyroidism
- Creatinine clearance value: to assess renal function in patients with chronic renal failure 2
- Serum alkaline phosphatase levels: to assess bone metabolism in patients with chronic renal dialysis 2
- Parathyroid hormone levels: to assess the effectiveness of calcitriol treatment in patients with hypocalcemia 2
From the Research
Labs Indicated for Hypocalcemia
The following labs are indicated for hypocalcemia:
- Serum calcium level 3, 4, 5, 6, 7
- Serum phosphate level 4, 5, 6, 7
- Parathyroid hormone (PTH) level 3, 4, 5, 6, 7
- Vitamin D level 3, 6, 7
- Alkaline phosphatase level 6, 7
Specific Lab Tests
Some specific lab tests that can be used to diagnose and manage hypocalcemia include:
- Serum calcium and phosphate measurements to assess the severity of hypocalcemia and guide treatment 3, 4, 5
- PTH measurement to differentiate between PTH-mediated and non-PTH mediated hypocalcemia 3, 4, 7
- Vitamin D measurement to assess for vitamin D deficiency, which can contribute to hypocalcemia 3, 6, 7
Lab Tests for Specific Causes of Hypocalcemia
Some lab tests that can be used to diagnose specific causes of hypocalcemia include: