Stability of 17α-Hydroxyprogesterone in Dried Blood Spots after Autoclaving and Prolonged Storage

Abstract

In the last few decades, management of patients with inborn errors of metabolism or congenital endocrine disorders has been greatly improved by the introduction of neonatal mass screening programs in many parts of the world. For this purpose, blood from newborns, ideally 4–7 days of age, is collected on filter-paper cards by means of a heel prick. A standard set of up to 20 tests is usually carried out at a centralized laboratory within a few days. Until recently, either when the tests were being performed or during the final step, the entire filter-paper card was autoclaved and then stored (1). Thus, leftover blood spots on filter paper from the entire young population in many countries are available in native or autoclaved form, although autoclaving has now become outdated because of a change in analytical methods (1). The stored cards provide a potentially valuable source for population studies or retrospective examinations. Documentation of the long-term stability of the analytes to be examined is a prerequisite for such studies. In many countries, the latest addition to the neonatal screening program is the examination for congenital adrenal hyperplasia (CAH), by measurement of 17α-hydroxyprogesterone (17-OHP) in a dried blood spot (2)(3)(4). The technique, first described by Pang et al. in 1977 (5), is based on a direct immunoassay and is used as the standard procedure in programs screening for CAH (2). In several trials, 17-OHP in dried blood spots on filter-paper cards was resistant to freezing, high ambient temperatures, humidity, and short- or intermediate-term (up to 1 year) storage (6)(7)(8)(9)(10). In the present study, we examined the impact of autoclaving (i.e., extremely high temperature, high humidity and pressure) and prolonged (more than a decade) storage under typical room conditions on the …