Abstract | Background: Reference ranges for testosterone are essential for making a diagnosis of hypogonadism in men.

Objective: To establish harmonized reference ranges for total testosterone in men that can be applied across laboratories by cross-calibrating cohort-specific assays to a reference method and standard.

Population: 9054 community-dwelling men in cohort studies in the United States and Europe: Framingham Heart Study; European Male Aging Study; Osteoporotic Fractures in Men Study; Male Sibling Study of Osteoporosis.

Methods: Testosterone concentrations in 100 participants in each of the four cohorts were measured using a reference method at Centers for Disease Control. Generalized additive models and Bland-Altman analyses supported the use of normalizing equations for transformation between cohort-specific and CDC values. Normalizing equations, generated using Passing-Bablok regression, were employed to generate harmonized values, which were used to derive standardized, age-specific reference ranges.

Results: Harmonization procedure reduced inter-cohort variation between testosterone measurements in men of similar ages. In healthy nonobese men, 19-39 years, harmonized 2.5th, 5th, 50th, 95th and 97.5th percentile values were 264, 303, 531, 852 and 916 ng/dL, respectively. Age-specific harmonized testosterone concentrations in nonobese men were similar across cohorts and greater than in all men.

Conclusion: The harmonized normal range (2.5th-to-97.5th percentile) in nonobese, population of European and American men, 19-39 years, is 264-916 ng/dL. A substantial proportion of inter-cohort variation in testosterone levels is due to assay differences. These data demonstrate the feasibility of generating harmonized reference ranges for testosterone that can be applied to assays, which have been calibrated to a reference method and calibrator.

Thomas G. Travison Hubert W. Vesper Eric Orwoll Frederick Wu Jean Marc Kaufman Ying Wang Bruno Lapauw Tom Fiers Alvin M. Matsumoto Shalender Bhasin

(2017) jc.2016-2935. DOI: https://doi.org/10.1210/jc.2016-2935
Published: 10 January 2017

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