Which statement best describes testing recommendations for vitamin D?

Testing for total vitamin D, particularly when screening for deficiency, is crucial because it provides a comprehensive assessment of a patient’s vitamin D status. The total vitamin D level reflects both the D2 (ergocalciferol) and D3 (cholecalciferol) forms of the vitamin, which are important for evaluating overall vitamin D sufficiency.

Vitamin D is vital for calcium homeostasis and bone health, and deficiencies can lead to serious health issues. By measuring total vitamin D, healthcare providers can determine if a patient has adequate levels, especially in populations at risk of deficiency, such as the elderly, those with limited sun exposure, or individuals with certain medical conditions.

While specific measurements of the 1,25(OH)D3 form can provide useful information in specific clinical situations, such as diagnosing certain disorders like primary hyperparathyroidism, evaluating total vitamin D is sufficient and more widely applicable for screening purposes. Thus, testing for total vitamin D is the recommended practice when assessing vitamin D deficiency in the general population.