Vitamin D
What is analysed?
Vitamin D is an essential fat-soluble vitamin that plays an important role in various physiological functions, including calcium and phosphate regulation, immune system function, bone health, and cellular growth and differentiation. The vitamin D test measures vitamin D levels in the blood.
What does the result mean?
The result indicates the concentration of vitamin D in the blood.
Why conduct the analysis?
The vitamin D test is conducted to evaluate dietary intake and sunlight exposure, and assess the risk of rickets and osteomalacia.
When to conduct the analysis?
The vitamin D test is conducted when symptoms of vitamin D deficiency, such as bone pain, muscle weakness or fatigue, are observed. The analysis may also be conducted during bone health assessments and regular monitoring of patients at risk for vitamin D deficiency like elderly patients.
What sample is required?
A blood sample is used for the analysis of vitamin D levels. The blood is drawn from a vein, usually in the arm.
Is any prior preparation necessary?
Patients should fast for 8-12 hours before the blood sample is taken. In addition, patients should also inform a healthcare professional about any medications being taken, as they could affect results.
How is it performed?
The collected sample is sent to a laboratory, where it is analysed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) or immunoassay techniques to quantify vitamin D levels in the blood.
What are the normal values?
| Interpretation | Vitamin D levels |
|---|---|
| Deficient | <20 ng/mL |
| Insufficient | 20-29 ng/mL |
| Sufficient/optimal | 30-100 ng/mL |
| Excess | >100 ng/mL |
What does having altered values mean?
- Low levels: Low vitamin D levels indicate vitamin D deficiency, which can lead to bone conditions such as rickets and osteomalacia.
- Elevated levels: Raised vitamin D levels can lead to hypercalcaemia (too much calcium in the body), which can cause weakened bones and damage to the kidneys and the heart.