Surrogate markers for diagnosis of vitamin D deficiency

Background/objectives Vitamin D deficiency is becoming a pandemic problem. Hypovitaminosis-D is diagnosed by measuring 25-hydroxyvitamin D in blood. In Egypt this costs 500 EGP, whereas one ampoule containing 200 000 units of vitamin D costs 5 EGP. Therefore, we need markers for vitamin D deficiency that are affordable. Materials and methods We conducted a cross-sectional study on 90 healthy patients aged 20–60 years during spring and summer. Participants underwent history taking, clinical examination, and measurements of hemoglobin, creatinine, calcium (Ca) (total and ionized), phosphorus, magnesium, parathyroid hormone (PTH), and 25-hydroxyvitamin D. Results The prevalence of vitamin D deficiency (<20 ng/ml) was 73.33%, that of insufficiency (21–30 ng/ml) was 25.56%, and that of vitamin D sufficiency (>30 ng/ml) was only 1.11% in the samples tested. PTH had a significant inverse correlation with vitamin D level (r=−0.2), whereas serum Ca (total and ionized) and phosphorus had a positive correlation. By receiver operating characteristic curve the predictive accuracy of PTH was 70%, whereas that of total Ca was 38%, ionized Ca was 43%, and phosphorous was 60.7%. Conclusion Measurements of PTH, Ca, and phosphorus can be used as markers for vitamin D deficiency; these tests cost less than 200 EGP, resulting in 60% savings in the cost of diagnosis of this widely prevalent condition.