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Serum Calcium Level (Total)

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

This test measures the amount of calcium in your blood serum, which is important for maintaining healthy bones, muscles, nerves, and overall body function.

Quick summary

["Calcium levels help ensure strong bones and proper nerve/muscle function."]

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

Key facts at a glance

LOINC
103445-3
Short code
XR Clavicle-L 1V
Synonyms
XR Clavicle-L 1V
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
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 Is This Test Done?

Your healthcare provider may order this test to check for conditions like low or high calcium levels, which can cause symptoms such as muscle cramps, weakness, or irregular heart rhythms. It may also be used to monitor conditions like osteoporosis, kidney disease, or certain hormonal imbalances.

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 it involves drawing blood from a vein. Wear comfortable clothing and plan to stay near the testing site for a short time.

What Happens During the Test?

A healthcare professional will insert a small needle into a vein in your arm or hand to draw blood. You may feel a slight prick or pinch, but it should only take a few minutes. The blood is then sent to a lab for analysis.

What Are Possible Results?

Results are compared to standard reference ranges, but exact values can vary by lab. Low calcium may indicate conditions like vitamin D deficiency or kidney problems, while high levels could suggest overuse of certain medications or thyroid disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal calcium levels can affect many body systems. Low calcium can weaken bones, cause muscle spasms, or increase the risk of seizures. High calcium may lead to kidney stones, heart issues, or fatigue. Regular monitoring helps manage these risks effectively.

Short name

Total Serum Calcium

Frequently asked questions

What causes low calcium levels?
Low calcium can result from dietary deficiencies (e.g., lack of vitamin D or calcium-rich foods), kidney problems, certain medications, or hormonal imbalances like hypoparathyroidism.
How is calcium usually treated?
Treatment depends on the cause. Dietary changes (e.g., more dairy, leafy greens) or supplements (vitamin D, calcium) may help. Severe cases may require medical interventions like intravenous calcium or hormone therapies.
Can calcium levels change with diet?
Yes, diet plays a key role. Foods high in calcium (milk, cheese, leafy greens) and vitamin D (sunlight, fatty fish) can influence blood levels. Avoiding excessive caffeine or alcohol may also help maintain balance.
  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