Estradiol Serum Levels are Crucial to Understand Physiological/Clinical Setting in Both Sexes: Limits of Measurement of Low Estradiol and Evaluation of a Sensitive Immunoassay (original) (raw)
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High-sensitivity measurement of serum estrogens is important in adult and pediatric endocrinology and oncology. We developed a high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for simultaneous measurement of estrone (E 1 ) and estradiol (E 2 ). Aliquots of 200 µL of serum were spiked with internal standard, extracted, derivatized with dansyl chloride, and analyzed by LC-MS/MS using 2-dimensional chromatographic separation. Total imprecision for the method was less than 11%; the limit of quantitation was 1 pg/mL. Reference intervals were established with samples from more than 900 healthy postmenopausal women, men, girls, and boys. Concentrations of estrogens in children reached adult levels by Tanner stage 3. In men and postmenopausal women, the median concentrations of total estrogens (E 1 + E 2 ) were 39 and 22 pg/mL, and the median E 2 /E 1 ratios were 0.98 and 0.55, respectively. The method requires a small sample volume and has adequate sensitivity and specificity for analyzing estrogens in samples from postmenopausal women, men, and children.
Clinica Chimica Acta, 2008
Background: Measurement of estradiol (E 2 ) plays a critical role in the diagnosis and clinical management of reproductive disorders. The challenge for all currently available direct methods for measuring E 2 is to provide accuracy and precision across a wide dynamic range. Methods: We describe the development and multi-site performance evaluation of a direct E 2 assay on the Architect i2000®. Assay performance and method comparisons were performed by testing specimens from men, healthy women with regular menstrual cycles, and post-menopausal women using the Architect assay and isotope dilution, gas chromatography-mass spectrometry (ID/GC-MS). Reference intervals were established by testing prospectively collected daily blood draws from 42 healthy women, 72 postmenopausal women and 101 males. Results: No unexpected cross-reactivity or interference was observed for over 40 compounds tested. Recovery was 100 ± 10% in the presence of estrone and estriol. Functional sensitivity (%CV b 20%) was b15 pg/ml. 1 The imprecision of the assay was b 7.1% (total CV), b 2.5%, and b2.3% for control sera containing 45, 190, and 600 pg/ml estradiol, respectively. The assay had a correlation of y = 1.033 x + 0.3156, r 2 = 0.99, n = 131 compared to ID/GC-MS. Reference intervals for the current Architect Estradiol assay are reported. Conclusions: Format changes resulted in dramatic improvement in the performance and accuracy of this direct, fully automated assay. The assay is standardized by ID/GC-MS. The assay is clinically useful for serum concentrations from 15 to N 4000 pg/ml. (P.M. Sluss).
Human Reproduction, 2007
BACKGROUND: In 2005, a special survey in the Belgian External Quality Assessment focused on the performance of six automated immunoassay analysers most frequently used in Belgium for estradiol-17b (E 2 ) and progesterone. Results obtained were compared with values determined by reference method, isotope dilution-gas chromatograph/mass spectrometry (ID-GC/MS). METHODS: Five fresh frozen serum samples, without additives, from single donors and three pools from pregnant women were distributed to all registered Belgian laboratories. Total variation, bias, linear relationship within the reported range and linear regression were investigated. RESULTS: Inter-laboratory coefficients of variation ranged from 4 to 49% for E 2 and from 6 to 45% for progesterone. Bias ranged from 226 to 239% for E 2 and from 223 to 81% for progesterone. Several systems showed an upward bias for one particular sample of at least 25%. Weighted linear regression showed overall bias ranging from 28% to 32% for E 2 and from 7% to 41% for progesterone. CONCLUSIONS: Few automated methods succeed in having an excellent reproducibility for E 2 and progesterone. Given the high bias values it is suggested that, for performance testing, results be compared whenever possible with a reference method. The linear relationship as assessed by comparing results with those obtained by ID -GC/MS using samples from different donors was not assured for most methods.
Performance of Direct Estradiol Immunoassays with Human Male Serum Samples
Clinical Chemistry, 2014
BACKGROUND: Steroid immunoassays originally required solvent extraction, chromatography, and structurally authentic tracers to avoid interference from steroid cross-reactivity and matrix effects. The demand for steroid assays has driven assay simplification, bypassing this triplet of validity criteria to allow use of unextracted serum, which has introduced bias and nonspecificity at low steroid concentrations. We aimed to evaluate the performance of commercial direct estradiol (E 2 ) immunoassays relative to the reference method of LC-MS and compared serum E 2 measurements from each assay with biomarkers of estrogen action.
High-Sensitivity Tandem Mass Spectrometry Assay for Serum Estrone and Estradiol
American Journal of Clinical Pathology, 2008
High-sensitivity measurement of serum estrogens is important in adult and pediatric endocrinology and oncology. We developed a high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for simultaneous measurement of estrone (E 1 ) and estradiol (E 2 ). Aliquots of 200 µL of serum were spiked with internal standard, extracted, derivatized with dansyl chloride, and analyzed by LC-MS/MS using 2-dimensional chromatographic separation. Total imprecision for the method was less than 11%; the limit of quantitation was 1 pg/mL. Reference intervals were established with samples from more than 900 healthy postmenopausal women, men, girls, and boys. Concentrations of estrogens in children reached adult levels by Tanner stage 3. In men and postmenopausal women, the median concentrations of total estrogens (E 1 + E 2 ) were 39 and 22 pg/mL, and the median E 2 /E 1 ratios were 0.98 and 0.55, respectively. The method requires a small sample volume and has adequate sensitivity and specificity for analyzing estrogens in samples from postmenopausal women, men, and children.
Bionatura, 2020
Estradiol is one factor that can alter the outcome of the treatment of infertile couples following the application of in vitro fertilization techniques. Currently, the estradiol level is measured by two diagnostic methods Enzyme-Linked Immunosorbent Assay (ELISA) and Electrochemiluminescence (ECL). Accordingly, this study determines ELISA and ECL's sensitivity and consistency to measure different levels of estradiol and determine its reliable range and provide this information to laboratories and gynecologists. This study is performed on 250 patients of the Avicenna Fertility Center. The data of the study are analyzed in SPSS18 and MiniTab. Consent was obtained for experimentation with human subjects. Pearson correlation coefficient was used to investigate the relationship between these two methods. The results indicated a strong correlation between the two variables ECL and ELISA ( r= 0.735, P-value<0.001). High numbers indicate that the decrease and increase of one variable...