(372) Does Age Predict the Difference in Morning vs Afternoon Testosterone Levels?

Abstract Introduction It is recommended that serum testosterone (T) level measurement be conducted in the early morning (AM) as T levels decrease afternoon (PM) due to circadian rhythm secretion. This reported blunted older men. Objective study aimed define magnitude and direction of changes between across age groups. Methods The population included men who had both AM (before 10 am) PM (after 2 pm) total (TT) within 3 months each other. All TT measurements were performed using LCMS. We excluded patients with a prior orchiectomy, 1000 ng/dL, those history androgen deprivation therapy, on therapy. Differences quantified stratified by continuously. directionality based increases or decreases vs PM. No difference was defined delta -100 + 100 increasing decreasing >100 ng/dL. Correlation calculated. Results 506 analyzed. Mean = 63 ± 12 years. 425 164 ng/dL 397 155 respectively (p < 0.001). While 63% no significant (-100 +100) levels, 24% > ng/dl decrease, 13% increase. Overall, higher lower levels. Neither nor significantly associated age. Age weakly negatively correlated change (r 0.10, p 0.03). That is, mean more pronounced for ages approached zero increased. Conclusions not this did find differences Disclosure