Enzyme immunoassay for total immunoglobulin E in dried blood spots.

Elevated circulating levels of total immunoglobulin E (IgE) are associated with both allergic disease and repeated macro-parasitic infections. Population-based research on IgE has been limited by the logistical constraints associated with obtaining and processing venipuncture blood samples. In this short report, we present an enzyme immunoassay protocol for quantifying circulating total IgE levels in capillary whole blood, collected from a finger prick and dried on filter paper. The assay demonstrated acceptable levels of accuracy, precision, and reliability. IgE remained stable at room temperature for only 2-4 days and degraded rapidly at higher temperatures suggesting that samples should be refrigerated or frozen within 1-2 days of collection. It is hoped that the relative ease of blood spot collection will expand opportunities for population-based research on IgE.