Description
Overview: Your body gets Vitamin D from three sources: sunlight, diet (fatty fish, egg yolks, fortified foods), and supplements. Your liver converts all these forms into 25-hydroxyvitamin D (25(OH)D), which is the primary circulating form in the blood. This test measures the total amount of 25(OH)D (both D2 from plants and D3 from animals/sun), providing the best indicator of your overall Vitamin D status.
Clinical Significance:
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Bone Health: Vitamin D is critical for your body to absorb calcium. Deficiency can lead to soft, weak, or brittle bones, causing conditions like rickets in children and osteomalacia or osteoporosis in adults.
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Deficiency is Common: Many people are deficient without knowing it, especially those with limited sun exposure, dark skin, older adults, obese individuals, and those with malabsorption conditions (like Crohn’s or celiac disease).
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Overall Health: Beyond bones, adequate Vitamin D is vital for muscle function, nerve signaling, and a healthy immune system. Low levels have been linked to an increased risk of certain autoimmune diseases, infections, and even some cancers.
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Toxicity: This test also helps monitor for Vitamin D toxicity (hypervitaminosis D), which can occur from taking too many supplements and can cause dangerous calcium buildup.
When is this test recommended?
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For individuals with symptoms of deficiency like bone pain, muscle weakness, or fatigue.
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To screen high-risk groups, including the elderly, people with dark skin, those who get little sun, and patients with osteoporosis or malabsorption disorders.
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To monitor patients taking Vitamin D supplements to ensure they are reaching a healthy level without becoming toxic.
Sample Requirements:
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Specimen: Serum.
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Container: Gold Top (SST) or Red Top Tube.
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Preparation: Fasting is not typically required, but check with your lab for specific instructions.
