What is a 25 OH vitamin D deficiency level?
                                
                                
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                                    4 min read                                
                            
                                According to Medscape, vitamin D deficiency is typically defined as a serum 25-hydroxyvitamin D (25[OH]D) level of less than 20 ng/mL. This circulating form of vitamin D is the most accurate marker for determining the body's vitamin D status.