Vitamin D deficiency occurs when your body lacks adequate levels of vitamin D, an essential nutrient for bone health, immune function, and calcium absorption. It is caused by insufficient sun exposure, inadequate dietary intake, malabsorption disorders, or kidney and liver diseases that prevent vitamin D activation. The Vitamin D, 1,25-Dihydroxy, LC/MS/MS test is the most important test for diagnosis because it measures the active form of vitamin D in your blood.
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Vitamin D deficiency is caused by insufficient sun exposure, inadequate dietary intake, malabsorption disorders, or impaired kidney and liver function. Your body produces vitamin D when your skin is exposed to sunlight, specifically UVB rays, but factors like living in northern latitudes, wearing sunscreen consistently, having darker skin, or spending most time indoors can limit production. Additionally, conditions like Crohn disease, celiac disease, and kidney or liver disease can prevent your body from absorbing or converting vitamin D into its active form, leading to deficiency even with adequate sun exposure.
The Vitamin D, 1,25-Dihydroxy, LC/MS/MS test is the most important test for vitamin D deficiency because it measures the active form of vitamin D in your blood, including both vitamin D2 and D3 metabolites. This test provides the most accurate assessment of your vitamin D status and can detect deficiency that may lead to bone diseases like rickets in children and osteomalacia in adults. For a more comprehensive evaluation, especially if you have other health concerns, the Post COVID-19 Expanded Panel includes vitamin D testing along with other important markers that can identify deficiency manifesting as bone pain and muscle weakness.
You should get tested if you experience bone pain, muscle weakness, frequent infections, fatigue, or mood changes like depression. Testing is especially important if you have limited sun exposure, darker skin, are over age 65, have obesity, kidney or liver disease, or take medications that interfere with vitamin D absorption. You should also consider testing if you have conditions like osteoporosis, inflammatory bowel disease, or if you are pregnant or breastfeeding, as these situations increase your risk of deficiency and require optimal vitamin D levels for health.
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What this means
Your active vitamin D levels are slightly below the optimal range. While this is not severely low, it may contribute to reduced calcium absorption, bone weakness, or persistent fatigue. This is especially important to address if you have kidney disease or calcium imbalances.
Recommended actions
Discuss vitamin D supplementation with your doctor, especially if you have kidney issues
Ensure adequate calcium intake through dairy, leafy greens, or fortified foods
Get regular sunlight exposure when possible (10-30 minutes several times weekly)
Support kidney health with proper hydration and blood pressure management
Retest in 8-12 weeks after implementing changes
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