for the patient’s age and sex. However, current immunoassays for testosterone are prone to interferences in the female reference range (low levels of testosterone) and can be inaccurate ( 7 , 8 , 9 ). Liquid chromatography–tandem mass spectrometry
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Sandra R Dahl, Ingrid Nermoen, Ingeborg Brønstad, Eystein S Husebye, Kristian Løvås, and Per M Thorsby
Niek F Dirks, Etienne Cavalier, and Annemieke C Heijboer
). Measurement results are therefore to be reported in ‘nmol/L’ in the case of 25(OH)D and 24,25(OH) 2 D or ‘pmol/L’ for 1,25(OH) 2 D. Measurement preanalysis For 25(OH)D, both automated assays and liquid chromatography–tandem mass spectrometry (LC-MS/MS
Johanna Christina Penell, Mark M Kushnir, Lars Lind, Jonatan Bergquist, Jonas Bergquist, P Monica Lind, and Tord Naessen
concentrations seen in elderly ( 25 , 26 , 27 ). We recently developed highly sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods to identify and quantify a large number of steroids in small sample volumes ( 13 , 14 , 16
Lauren R Cirrincione, Bridgit O Crews, Jane A Dickerson, Matthew D Krasowski, Jessica Rongitsch, Katherine L Imborek, Zil Goldstein, and Dina N Greene
effect of unconjugated estrone concentrations on estradiol immunoassay interference, we determined analytical bias relative to liquid chromatography tandem mass spectrometry (LC-MS/MS) in three estradiol commercial immunoassays among transgender women
Amalie Carlsson, Kaspar Sørensen, Anna-Maria Andersson, Hanne Frederiksen, and Anders Juul
one out of nine environmental phenols measured by liquid chromatography-tandem mass spectrometry (LC–MS/MS) with prior enzymatic deconjugation ( 19 , 20 ). For the present study, first morning urine collected from the first of the two consecutive
M Krause, H Frederiksen, K Sundberg, F S Jørgensen, L N Jensen, P Nørgaard, C Jørgensen, P Ertberg, J H Petersen, U Feldt-Rasmussen, A Juul, K T Drzewiecki, N E Skakkebaek, and A M Andersson
-I. Chemical analysis of UV filters Maternal urine and serum samples were analyzed for seven different UV filters by isotope dilution TurboFlow-liquid chromatography–tandem mass spectrometry (LC–MS/MS) ( 25 ), and the measured concentrations have previously
M P Schuijt, C G J Sweep, R van der Steen, A J Olthaar, N M M L Stikkelbroeck, H A Ross, and A E van Herwaarden
Objective
Increased maternal testosterone concentration during pregnancy may affect the fetus. Therefore it is clinically relevant to have a quick and reliable method to determine free testosterone levels. Current calculators for free testosterone are suspected to perform poorly during pregnancy due to suggested competition between high levels of estradiol and free (bio-active) testosterone for sex hormone-binding globulin (SHBG) binding. Therefore, it is claimed that reliable calculation of free testosterone concentration is not possible. However, recent evidence on SHBG-binding sites questions the estradiol effect on the testosterone-SHBG binding during pregnancy. In this study, we investigated whether the free testosterone concentration can be calculated in pregnant women.
Design and methods
Free testosterone was measured with a specially developed equilibrium dialysis method combined with liquid chromatography tandem mass spectrometry (LC-MS/MS). Free testosterone was also calculated with the formulas of Vermeulen et al. and Ross et al.
Results
Total and free testosterone measured in healthy men and women were in good agreement with earlier reports. In pregnant women, total testosterone values were higher than in non-pregnant women, whereas free testosterone values were comparable. Calculated free testosterone levels in pregnant women were highly correlated, but marginally higher, compared to measured free testosterone levels.
Conclusions
We developed an equilibrium dialysis–LC-MS/MS method for the measurement of free testosterone in the low range of pregnant and non-pregnant women. Although during pregnancy total testosterone is increased, this is not the case for free testosterone. The free testosterone formulas perform well in pregnant women.
Filippo Ceccato, Elisa Selmin, Giorgia Antonelli, Mattia Barbot, Andrea Daniele, Marco Boscaro, Mario Plebani, and Carla Scaroni
), because outdated radioimmunoassays were not able to differentiate compounds with structural similarity to the target molecule as cortisone (E) and F ( 9 , 10 ). The use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) is increasing, and
Letícia Ribeiro Oliveira, Carlos Alberto Longui, Guilherme Guaragna-Filho, José Luiz Costa, Rafael Lanaro, David Antônio Silva, Maria Izabel Chiamolera, Maricilda Palandi de Mello, André Moreno Morcillo, Andrea Trevas Maciel-Guerra, and Gil Guerra-Junior
testosterone, DHEA, testosterone-d3 (IS1), and androstenedione by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Compound Retention time (min) MRM Collision energy (eV) DP (V) CXP (V) Testosterone 6.57 288.8 → 97
Maki Igarashi, Tadayuki Ayabe, Kiwako Yamamoto-Hanada, Keiko Matsubara, Hatoko Sasaki, Mayako Saito-Abe, Miori Sato, Nathan Mise, Akihiko Ikegami, Masayuki Shimono, Reiko Suga, Shouichi Ohga, Masafumi Sanefuji, Masako Oda, Hiroshi Mitsubuchi, Takehiro Michikawa, Shin Yamazaki, Shoji Nakayama, Yukihiro Ohya, and Maki Fukami
of age or later ( 1 , 4 , 5 , 6 ). Thus, sexual dimorphism in blood sex hormone levels is evident in children above 8 years of age. Furthermore, ultra-sensitive hormone assays using liquid chromatography-tandem mass spectrometry (LC-MS/MS) have
