What is the Calcium + Vitamin D Test?

The Calcium + Vitamin D test measures two closely linked nutrients that are essential for bone strength, muscle function and overall metabolic health. Calcium is a key mineral required for bone structure, nerve transmission and muscle contraction, while vitamin D is necessary for proper calcium absorption from the gut.

Vitamin D regulates how much calcium enters the bloodstream and how effectively it is used by bones. Even with adequate calcium intake, low vitamin D levels can lead to poor calcium absorption, weakened bones and long-term skeletal issues.

Testing both markers together provides a more complete picture of bone metabolism and mineral balance than measuring either alone.

Why do I need a test for Calcium and Vitamin D?

You may need this test if there is concern about bone health, fatigue, muscle symptoms or nutritional deficiency. Calcium and vitamin D imbalance is common, particularly in individuals with limited sun exposure, dietary restrictions or absorption problems.

This test is also widely used in the investigation of osteoporosis risk, recurrent fractures, parathyroid disorders and unexplained calcium abnormalities on routine blood tests.

Symptoms and scenarios where testing is recommended:

• Bone pain or frequent fractures
• Muscle weakness or cramps
• Fatigue or low energy
• Osteoporosis or osteopenia risk
• Limited sun exposure
• Malabsorption or digestive disorders
• Postmenopausal bone health assessment
• Thyroid or parathyroid disorders
• Monitoring vitamin D supplementation

Benefits of the Calcium + Vitamin D Test

• Provides a complete view of bone metabolism
  Assesses both mineral levels and absorption capacity.
• Identifies vitamin D deficiency early
  Helps prevent long-term bone and muscle complications.
• Supports osteoporosis risk assessment
  Useful in fracture prevention strategies.
• Explains muscle and fatigue-related symptoms
  Deficiency can cause neuromuscular symptoms.
• Guides supplementation decisions
  Helps tailor calcium and vitamin D intake safely.
• Supports parathyroid and endocrine evaluation
  Calcium imbalance may reflect hormonal disorders.
• Useful across all age groups
  Relevant for children, adults and older individuals.
• Simple and widely used blood test
  Requires only a standard blood sample.

Step-by-Step: How Testing Works

Choose your preferred testing method

You can attend one of our UK partner clinics or arrange a home or hotel visit with a mobile phlebotomist.

Option 1 – In-Clinic Blood Draw

1. Select your nearest UK clinic and book an appointment.
2. A clinician or phlebotomist collects a venous blood sample.
3. The sample is analysed for calcium and vitamin D levels.
4. Results are delivered securely online.

Option 2 – Home or Hotel Phlebotomy (+£60)

1. Book a UK-wide home or hotel visit at a convenient time.
2. A trained phlebotomist collects your blood sample on-site.
3. The sample is packaged and transported to the laboratory.
4. Results are uploaded digitally without the need to travel.

Access your report

You can download and share your results with your GP or healthcare professional for interpretation.

Your Results Explained

Low Levels

Low calcium or vitamin D levels suggest deficiency or impaired absorption.
This may increase the risk of weak bones, fractures and muscle symptoms.
Typical UK reference ranges:

• Calcium: ~2.2–2.6 mmol/L
• Vitamin D (25-OH): <50 nmol/L indicates deficiency

Normal Levels

Normal results indicate balanced mineral levels and effective vitamin D absorption.
This supports healthy bone structure and muscle function.

High Levels

Elevated calcium may suggest parathyroid disorders or excessive supplementation.
High vitamin D levels are uncommon but may occur with excessive intake.
Abnormal results usually prompt further endocrine or metabolic assessment.