Purpose: To compare the diagnostic accuracy of plasma aldosterone concentration (PAC), renin activity (PRA) and aldosterone-to-renin ratio (ARR) in primary aldosteronism (PA) using radioimmunoassay (RIA) chemiluminescence immunoassay (CLIA) methods.
 Methods: Both RIA CLIA were used to analyze PAC, PRA ARR with subjects standing or supine position, before after a saline infusion tes...

We describe a gentamicin assay in which a peroxidase-gentamicin conjugate competes with gentamicin for binding to a gentamicin antibody adsorbed to a polystyrene solid phase. The assay can be completed in 30 min and requires 50 microliter of diluted serum. The precision and accuracy are equivalent to that of a radioimmunoassay technique and the reagents are stable for several months.

The dose/response curve in enzyme-multiplied immunoassays (EMIT) and related techniques may be described by the same "four-parameter logistic function" as has proven useful in radioimmunoassays, immunoradiometric assays (IRMA), and two-site immunoradiometric ("sandwhich") assays. This function provides an empirical description of the dose/response curve by use of an objective least-squares regr...

The concentration of digoxin in the cerebrospinal fluid (CSF) of ten patients receiving conventional oral doses of this cardiac glycoside has been measured by a radioimmunoassay technique. Digoxin was undetected in eight patients and barely detectable in two, suggesting the presence of a significant blood-CSF barrier for digoxin. The implication of these findings is discussed.