[Log-normal distributed plasma cortisol levels of four daily measurements in normal subjects. A comparison of the fluorescence method after de Moor with a radioimmuno assay of plasma cortisol (author's transl)].

The present paper describes the plasma cortisol concentrations on four daily measurements in normal subjects assayed with the fluorescence method after de Moor and with a radioimmuno assay. A comparison of these two methods shows that the determinations of plasma cortisol with the fluorescence method always yielded higher values. Both methods are sensitive enough to detect the circadian rhythm of cortisol secretion. For the purpose of routine diagnostics it is sufficient to measure the maximal and minimal concentrations of plasma cortisol in blood samples taken at 8 a.m. and 8 p.m., respectively. The plasma cortisol measurements should only be attempted after allowing a few days of adaption to the hospital situation. Table 2 shows that the normal plasma cortisol levels are represented only by log-normal distributed values. These concentrations are lower than the linear distributed levels reported so far.