Table 1

Assay methods and median values of measured and calculated percentage of free E2 and percentage of non-SHBG bound E2

Blank entries in the table indicate that an assay was not performed for that study.

Study% free E2% non-SHBG-bound E2
Assay procedureMedian measuredMedian calculatedAssay procedureaMedian measuredMedian calculated
Columbia, United States (9 , 10)Centrifugal ultrafiltration (27)1.261.37Centrifugal ultrafiltration (27)43.6250.40
Guernsey, United Kingdom (11)1.2947.44
Nurses’ Health Study, United States (12)Equilibrium dialysis (28, 29)1.561.48Ammonium sulfate precipitation (2, 25)23.1954.49
Study of Hormones and Diet in the Etiology of Breast Tumors, Italy (13)1.5456.74
Rancho Bernardo United States (14 , 15)1.7765.13
Radiation Effects Research Foundation, Japan (16)1.33By addition, charcoal method (30)46.5548.90
Study of Osteoporotic Fractures, United States (17)Equilibrium dialysis (28, 29)1.561.56Ammonium sulfate precipitation (2, 25)35.4157.52
Washington County, United States (18 , 19)Ultrafiltration (27)1.471.3349.03
  • a Assays either measure percentage of non-SHBG-bound E2 or percentage of albumin-bound E2.