madman
Super Moderator
Introduction
AUA guidelines define testosterone deficiency as two levels < 300 ng/dL with signs/symptoms.Testosterone (T) measurement is performed using immunoassays (IA) or mass spectrometry (MS), with MS as the gold standard. However, limited data suggests there may be significant variation between assays, which may have implications for initiation and cessation of testosterone replacement therapy (TRT). The objective was to examine variation in testosterone assays and men at risk for unnecessary TRT treatment.
Methods
After IRB approval, we identified men with the following ICD 10 codes: T deficiency, hypogonadism, or erectile dysfunction. Men with the following labs drawn simultaneously were included: testosterone (IA), testosterone (MS), prostate specific antigen (PSA), free PSA, estradiol, luteinizing hormone (LH), and follicle stimulating hormone (FSH). Assays were compared and men were assessed for risk of potentially unnecessary TRT based on having an IA T <300 and MS T > 300 ng/dL.
Results
235 men (median age of 58.0 [IQR: 52] years old; BMI of 30.8 [IQR: 6.1]) underwent 328 serum assessments. The median T for IA versus MS were 275.0 (IQR: 217.2) and 346.0 (IQR: 288) ng/dL respectively (p < 0.0001). When dividing the IA labs into 100 ng/dL groups with their paired MS results, there was a significant difference (p <0.05) across all groups except IA levels less than 100 ng/dL (p > 0.05). Men with IA T levels in the range of 201-300 were assessed for being at risk for TRT. 57.6% (n = 53) of measurements for men were at risk for unwarranted TRT. Testosterone to estradiol (T:E) ratios were compared. The median ratios for IA/MS were 10.8 (IQR: 6.7) and 13.9 (IQR: 9.2) respectively (p< 0.001). When examining those at risk for aromatase inhibitor (AI) therapy based on a 10:1 T:E ratio 16.3% (n = 36) had an IA T:E ratio < 10:1 and MS T:E ratio > 10:1.
Conclusion
There is significant variability in T results between IA vs. MS assays. Utilization of IA may lead to overtreatment with TRT or AI therapy compared to MS assays. Urologists should be aware of these discrepancies as they consider diagnostic options and treatment of men with TD.
AUA guidelines define testosterone deficiency as two levels < 300 ng/dL with signs/symptoms.Testosterone (T) measurement is performed using immunoassays (IA) or mass spectrometry (MS), with MS as the gold standard. However, limited data suggests there may be significant variation between assays, which may have implications for initiation and cessation of testosterone replacement therapy (TRT). The objective was to examine variation in testosterone assays and men at risk for unnecessary TRT treatment.
Methods
After IRB approval, we identified men with the following ICD 10 codes: T deficiency, hypogonadism, or erectile dysfunction. Men with the following labs drawn simultaneously were included: testosterone (IA), testosterone (MS), prostate specific antigen (PSA), free PSA, estradiol, luteinizing hormone (LH), and follicle stimulating hormone (FSH). Assays were compared and men were assessed for risk of potentially unnecessary TRT based on having an IA T <300 and MS T > 300 ng/dL.
Results
235 men (median age of 58.0 [IQR: 52] years old; BMI of 30.8 [IQR: 6.1]) underwent 328 serum assessments. The median T for IA versus MS were 275.0 (IQR: 217.2) and 346.0 (IQR: 288) ng/dL respectively (p < 0.0001). When dividing the IA labs into 100 ng/dL groups with their paired MS results, there was a significant difference (p <0.05) across all groups except IA levels less than 100 ng/dL (p > 0.05). Men with IA T levels in the range of 201-300 were assessed for being at risk for TRT. 57.6% (n = 53) of measurements for men were at risk for unwarranted TRT. Testosterone to estradiol (T:E) ratios were compared. The median ratios for IA/MS were 10.8 (IQR: 6.7) and 13.9 (IQR: 9.2) respectively (p< 0.001). When examining those at risk for aromatase inhibitor (AI) therapy based on a 10:1 T:E ratio 16.3% (n = 36) had an IA T:E ratio < 10:1 and MS T:E ratio > 10:1.
Conclusion
There is significant variability in T results between IA vs. MS assays. Utilization of IA may lead to overtreatment with TRT or AI therapy compared to MS assays. Urologists should be aware of these discrepancies as they consider diagnostic options and treatment of men with TD.
