Reassessment of the definition of castrate levels of testosterone: implications for clinical decision making.
OBJECTIVE
Based on methods introduced in the late 1960s and no longer used, serum testosterone level in men after surgical castration was reported to be 50 ng/dL or less. Radioimmunoassay and, subsequently, chemiluminescent methods have supplanted the early analytic methods because of their improved accuracy and ease of testing. The purpose of this study was to define the castrate testosterone level in the era of chemiluminescent testing.


METHODS
After bilateral orchiectomy, serum testosterone (total) levels were measured prospectively in 35 prostate cancer patients.


RESULTS
The median testosterone value in this patient cohort was 15 ng/dL (0.5 nmol/L; 95% confidence interval 12 to 17 ng/dL).


CONCLUSIONS
In a contemporary series, castrate testosterone should be defined as less than 20 ng/dL (0.7 nmol/L). The important biologic and economic implications are discussed.
Oefelein
M G
MG
University Hospitals of Cleveland, Department of Urology/Case Western Reserve University, Cleveland, Ohio, USA.
Feng
A
A
Scolieri
M J
MJ
Ricchiutti
D
D
Resnick
M I
MI
D000368:Aged; D006801:Humans; D007118:Immunoassay / Q000379:methods / Q000706:statistics & numerical data; D008163:Luminescent Measurements; D008297:Male; D009919:Orchiectomy / Q000706:statistics & numerical data*; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000601:surgery; D009626:Terminology as Topic; D013739:Testosterone / Q000097:blood*
D013739:Testosterone