An interlaboratory study of an automated technique for the assay of urinary oestrogens

Some Ionic and Dilution Effects in the Measurement of Urinary Oestrogens in Pregnancy

“…This statement is made with specific reference to the studies carried out herein, whereas the study of other interfering factors (as yet unspecified) may yield contrary findings. This has been suggested by some recovery studies (Moscrop et al, 1974). However, any advantages of predilution may be offset by reduced sensitivity, a slower sampling rate, and a longer through-put time as indicated by comparing the data of Campbell and Gardner (1971) with that of Hainsworth and Hall (1971).…”

“…This difference is greater than can be accounted for by the experimental error of the method and has been shown to be related to storage (Moscrop et al, 1974). Storage appears to increase the recovery of oestriol added to urines, and it has been suggested that it is due to the presence of interfering radicals which cause quenching of the fluorescence produced by oestrogens.…”

“…The results suggest that the ionic effect is chemical rather than physical and that there is no advantage in including a predilution step in the analysis. Other means of removing the ionic effects have so far proved unsuccessful.Many workers have observed that there is a dilution effect in the measurement of urinary oestrogen by automated techniques-that is to say, the apparent total urinary oestrogen output is different in an undiluted specimen compared to a diluted specimen of the same urine (Ismail and Watson, 1974;Moscrop et al, 1974). This difference is greater than can be accounted for by the experimental error of the method and has been shown to be related to storage (Moscrop et al, 1974).…”

Maternal Plasma Free Oestriol and 24 Hour Urinary Oestriol Excretion in the Assessment of Foetal Outcome

“…Some authors (Shelley et al 1970;Powers and Roach 1974) have suggested that oestrogen/creatinine ratios could be used to overcome the diurnal vari¬ ations, but the results have not been convincing. Recently, auto¬ matic procedures with a high precision and clinical reliability have been reported (Moscrop et al 1974;Little et al 1975). Up to now the majority of results reported in the literature have been obtained by methods involving hydrolysis of urine, extraction and separation of the phenolic fraction, and colorimetry, photometry, fluorometry or gas-liquid chromatography.…”

Review article

“…The most recent developments are based on the performance of KOBER color reaction directly on urine followed by ITTRICH extraction and fluorimetry [15]. This permits the use of automated, continuous-flow Systems which allow up to 70 or more samples to be assayed each day with a high degree of precision [71,88] and clinicäl reliability [51 ]. It also seems to be the most accurate method, in terms of precision between different laboratories [91].…”