I have a 9 month old son who is still primarily on breast milk and I want to make sure his Vit D levels are sufficient. When and how are levels tested in infants? I had my levels tested in June and they were 110 (it was done by labcorp). So I stopped taking my vit D supplement as I figured with summer I would be getting plenty from the sun and my levels were already too high. How long does it take for the levels to change? When should I recheck my levels? Thank you for any info in this area of health and wellness.