Skin contamination by oestradiol gel--a remarkable source of error in plasma oestradiol measurements during percutaneous hormone replacement therapy.
OBJECTIVE
To study the consequence of skin contamination by oestradiol gel on circulating plasma oestradiol levels.


METHODS
We studied ten healthy, hysterectomized postmenopausal women who had used percutaneous oestradiol gel for at least 2 years. After wash-out period percutaneous dose of 1.5 mg 17beta-oestradiol was administered once a day in the evening. The gel was applied with a bare or gloved hand to an arm or thigh according to the schedule. Blood samples for assay of plasma oestradiol concentrations were collected from both cubital veins 12 h after gel administration, at baseline and every time after using the gel, for 2 weeks.


RESULTS
Plasma oestradiol concentrations were significantly higher in the gel-contaminated samples: in the cubital vein of the gel-applying arm and in the cubital vein of the forearm on which the gel had been spread.


CONCLUSIONS
Skin contamination by topical 17beta-oestradiol can distort plasma oestradiol measurements by giving much higher oestradiol concentrations than in reality there are in the systemic circulation. This has an important meaning when tailoring individual oestrogen therapy.
Department of Obstetrics and Gynecology, Tampere University Hospital, P. O. Box 2000, 33521 Tampere, Finland.
Tarja
T
Vihtamäki
Tiina
T
Luukkaala
Risto
R
Tuimala
D000279:Administration, Cutaneous; D004958:Estradiol / Q000032:analysis / Q000097:blood* / Q000627:therapeutic use*; D015914:Estrogen Replacement Therapy / Q000379:methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood / Q000187:drug effects; D012867:Skin / Q000737:chemistry*
D004958:Estradiol