Challenges to the accurate and precise measurement of testosterone include deficiencies in standardization, variable reference ranges, expenses related to gold standard equipment, and other challenges. Total testosterone remains the most accessible for standard laboratories, while free testosterone and bioavailable testosterone may be useful adjuncts, particularly in men with low borderline testosterone values. Mass spectrometry is the gold standard measurement modality for total testosterone, while equilibrium dialysis followed by direct assessment with a trusted method is the gold standard technique for measuring free testosterone. Although reference ranges may vary, efforts to adapt reference ranges to different populations include age-adjusted values.