Background: Given the huge impact of vitamin D deficiency on a broad spectrum of diseases such as rickets, osteoporosis, mineral bone disease-vascular calcification syndrome, infectious diseases, but also several types of cancer and CNS diseases, reliable and simple methods to analyze the vitamin D status are urgently needed.
 Methods: We developed an easy technique to determine the 25-OH vitamin D status from dried blood samples on filter paper. This allows determination of the 25-OH vitamin D status independently of venous blood taking, since only sampling of capillary blood is required for this new method. We compared the results of vitamin D measurements from venous blood of 96 healthy blood donors with those from capillary blood taken from the same patients at the same time. The capillary blood was dried on filter paper using the D-Vital ID dry-blood collection system.
 Results: 25-OH vitamin D concentration data from extracted dried capillary blood filters correlated very well with data obtained after direct measurement of venous blood samples of the same blood donor (R: 0.7936; p<0.0001). The correlation was linear over the whole range of 25-OH vitamin D concentrations seen in this study. A Bland-Altman plot revealed good agreement between both tests.
 Conclusions: The D-Vital ID dry-blood collection system showed an excellent performance as compared to the classical way of 25-OH vitamin D measurement from venous blood. This new technique will facilitate easy and reliable measurement for vitamin D status, in particular, in rural or isolated areas, developing countries, and field studies.

Vitamin D status from dried capillary blood samples.

Objective: To study the relationship of Vitamin D deficiency and some minerals metabolism in the children with sickle cell disease (SCD) in the city of Jeddah, western region of Saudi Arabia. Design: Measuring the concentration of serum 25(OH) Vitamin D, calcium, phosphorus and magnesium in children with SCD aged between newborn to 12 years old. Methods: A total of 51 children with sickle cell disease (both gender) included 28 males (54.9%) and 23 females (45.1%) aged between newborn and 12 years old and 70 healthy matching controls were admitted or visited sickle cell section in the Maternity and Children Hospital in the city of Jeddah. Fasting blood samples were collected and the serum was separated and stored at n30”C until the time of analysis. Serum 25 (OH) Vitamin D was determined using a commercially available kit (VDBP,Gc globulin), calcium, phosphorus and magnesium were measured using a clinical autoanalyser. Results: The patients were divided into two groups according to the ages. Group-A included 21 patients (both gender) aged between newborn and 6 years, group-B included 30 patients (both gender) aged between 7-12 years. The results obtained showed that the serum concentrations of 25(OH) Vitamin D in both patients groups were significantly lower than the healthy matching controls (P 0.05) and significantly higher in the serum magnesium of group-B (P<0.05). Conclusion: A significant relation between Vitamin D deficiency and children with sickle cell disease which is normal due to confined patients indoor. The serum calcium concentration had no affect in the early stage of ages but a significant lower appeared with increasing of ages. The serum magnesium concentration was higher in group-B which can be explained to the important role of Mg +2 in the nature of erythrocyte membrane in sickle cell patients.

B. Eichinger

Papers

Enzyme binding protein assay for 25-hydroxyvitamin d