REPRODUCIBILITY STUDIES AND INTERLABORATORY CONCORDANCE FOR ASSAYS OFSERUM HORMONE LEVELS - ESTRONE, ESTRADIOL, ESTRONE SULFATE, AND PROGESTERONE

Citation
Mh. Gail et al., REPRODUCIBILITY STUDIES AND INTERLABORATORY CONCORDANCE FOR ASSAYS OFSERUM HORMONE LEVELS - ESTRONE, ESTRADIOL, ESTRONE SULFATE, AND PROGESTERONE, Cancer epidemiology, biomarkers & prevention, 5(10), 1996, pp. 835-844
Citations number
22
Categorie Soggetti
Public, Environmental & Occupation Heath
ISSN journal
10559965
Volume
5
Issue
10
Year of publication
1996
Pages
835 - 844
Database
ISI
SICI code
1055-9965(1996)5:10<835:RSAICF>2.0.ZU;2-Q
Abstract
We conducted studies to measure sources of assay variability for estro ne, estradiol, estrone sulfate, and progesterone for postmenopausal wo men (It = 5) and for women in the mid-follicular (n = 5) and mid-lutea l (n = 5) phases of the menstrual cycle, A single blood sample from ea ch woman was divided into 2.5-ml aliquots and stored at -70 degrees C, and sets of two aliquots were sent at monthly intervals to each of th ree laboratories (four for progesterone). Each aliquot was analyzed in duplicate, Thus, within each menstrual category, we were able to esti mate the components of variance due to variation among women, variatio n among aliquots, variation among duplicate measurements, and variatio n among the 4 analysis days, Using the logarithm of assay measurements , we estimated the percentage of variance attributable to variation am ong women in each menstrual category, 100 <(rho)over tilde>, where <(r ho)over tilde> is the estimated intraclass correlation, For each assay , 100 <(rho)over tilde> exceeded 90% for midfollicular and mid-luteal women, For postmenopausal women, values of 100 <(rho)over tilde> excee d 84% for estrone in two laboratories, Values of 100 <(rho)over tilde> were lower for progesterone in postmenopausal women, although a value of 84% was estimated from one laboratory, These studies indicate that estrogen assays over a period of 3 months permit reliable comparisons among women in a given menstrual category, Progesterone measurements are likewise reliable for women in the mid-follicular and mid-luteal p hases but somewhat less satisfactory for postmenopausal women, These a ssessments of variability pertain only to laboratory techniques and do not allow for secular variation in intra-woman hormone levels, Moreov er, although these measurements tend to be reliable enough for making comparisons among women, estimates of coefficients of variation for es trogens are about 10% for mid-follicular and mid-luteal phase women an d about 11-20% for postmenopausal women, Coefficients of variation for progesterone are about 10% for mid-luteal, 20% for mid-follicular, an d 30% for postmenopausal women.