Vitamin A analysis in dried blood spots by HPLC

There are many advantages of measuring vitamin A in dried blood spots from a finger prick as compared to serum collected by venipuncture. The advantages include: easier collection, transport, and storage; accessibility to younger and more remote populations; and decreased risk of disease transmission. We have now performed the analysis of vitamin A in dried blood spots using HPLC. The correlation coefficient (r²) was 0.90 between serum retinol and blood spot retinol in samples that had been stored at -70 C for < 6 months from 17 normal adults. Blood spot retinol was compared to serum retinol measured by HPLC in a subset of 150 samples from pregnant women in a randomized vitamin A/β-carotene supplementation trial in Sarlahi District, Nepal. The blood spot samples were collected from Sept-Dec 1995, stored at -10 C to -70 C and analyzed August 1997. The r²s between serum retinol and blood spot retinol was 0.74 for all samples, 0.87 excluding 9 outliers, and 0.78 for serum retinol values <20μg/dL. These results indicate that blood spot retinol analysis is a viable technique for assessing the vitamin A status of populations.