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Calcium in Serum (Total)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of calcium present in your blood serum. Calcium is an essential mineral that plays a key role in muscle and nerve function, bone health, and maintaining normal blood clotting.

Quick summary

["Check your calcium levels to help prevent or manage conditions like low calcium (hypocalcemia) or high calcium (hypercalcemia)."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
73244-6
Short code
NIFEdipine ind plt IgM SerPl Ql FC
Synonyms
NIFEdipine ind plt IgM SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors may order a total serum calcium test to diagnose or monitor conditions such as bone diseases (e.g., osteoporosis), kidney problems, thyroid disorders, or certain cancers. It can also help assess calcium balance in people with symptoms like muscle spasms, confusion, or frequent urination.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your doctor specifies it. Bring any medications you’re taking, as some (like calcium supplements or certain antibiotics) can affect results.

During the Test

A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight sting, but the process is quick and usually painless. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). While reference ranges vary by lab, low or high levels may signal underlying health concerns that need further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Total Serum Calcium

Frequently asked questions

What might cause abnormal calcium levels?
Low calcium (hypocalcemia) can result from conditions like vitamin D deficiency, kidney disease, or excessive loss of calcium through urine or stool. High calcium (hypercalcemia) may be linked to overactive thyroid, certain cancers, or prolonged exposure to sunlight.
How often should I get this test?
Your doctor will determine the frequency based on your health status, symptoms, and treatment plan. Regular monitoring may be needed if you have chronic conditions like kidney disease or osteoporosis.
Can diet or supplements affect this test?
Yes—high intake of calcium-rich foods (e.g., dairy, leafy greens) or supplements can temporarily raise results. Avoid large amounts of calcium or vitamin D supplements 24–48 hours before testing unless instructed otherwise.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy