A vitamin D test is used to check the levels of vitamin D in your blood. The test is usually done if your health care provider thinks that a bone or other health condition you have could be …

Sep 28, 2025 · A vitamin D test measures your blood's vitamin D levels to see if they are too high or too low. Low vitamin D levels can increase your risk of bone disease and other severe …

Dec 11, 2025 · Key Takeaways A 25-hydroxyvitamin D test checks if your body has too much or too little vitamin D. The test involves a simple blood draw, and you don't need to fast …

Sep 2, 2024 · What is the hydroxy-25 vitamin D test? The most accurate measurement of your vitamin D levels is a 25-hydroxy vitamin D test. It measures your blood level of 25-OH vitamin …

Sep 5, 2025 · Vitamin D receptors are found throughout the body, including on immune cells, meaning it plays a pivotal role in modulating our immune response, potentially reducing the …

In general, there's nothing you have to do before this test, unless your doctor tells you to. A health professional uses a needle to take a blood sample, usually from the arm. When a blood …

Vitamin D Test A vitamin D test measures the amount of vitamin D in the blood. The vitamin D test is also called the 25-hydroxy vitamin D, or 25 (OH)D, test. Your body needs vitamin D to …