Comparison of an all-aqueous automated urine pregnancy oestrogen method with one using organic solvent extraction

A comparative study between an all-aqueous automated urine pregnancy oestrogen method and a well established one requiring organic solvent extraction showed good agreement (r = 0.992). Advantages offered by the all-aqueous method include a faster rate of sample analysis and elimination of the difficulties of phase separation. The storage of urine for 5 days did not affect the oestrogen concentration measured by the all-aqueous method. Glucose, which reduced the apparent oestrogen concentration, was readily removed by treatment of the urine with borohydride, and treated urines showed good recoveries. The recovery of oestrogen was inadequate when glucose was removed from urine by incubation with yeast, possibly due to the formation of acetaldehyde.