Precision of radioimmunoassay with emphasis on curve-fitting procedures.

Direct curve-fitting methods using a digital computer have been employed to analyze the calibration curves of commercial kits for the assay of digoxin, digitoxin, insulin, B12, and renin activity (angiotensin). Inconsistencies have been revealed that suggest some improvements in the commercial kits are desirable. It is not suggested that the use of these kits would yield data of uncertain clinical value, but it is suggested that improvements in consistency would enhance the clinical utility.