Table 1.

Analysis of studies examining serum free testosterone and total testosterone levels

Study	ADT utilized	Patients (n)	Method of measurement	Timing	Mean age (year)	Length of ADT (month)	FT	TT
Schweizer et al.4 2018	LHRH agonist	1191	TT: RIA FT: RIA and EqD		76		1.01 pg ml−1 (0.101 ng dl−1)	0.69 nmol l−1 (19.9 ng dl−1)
Schweizer et al.4 2018	Orchiectomy	56	TT: RIA FT: RIA and EqD		76		1.14 pg ml−1 (0.114 ng dl)−1	0.69 nmol l−1 (19.9 ng dl−1)
Schweizer et al.4 2018	Orchiectomy and androgen receptor blockage	27	TT: RIA FT: RIA and EqD		74		1.25 pg ml−1 (0.125 ng dl−1)	0.69 nmol l−1 (19.9 ng dl−1)
Schweizer et al.4 2018	LHRH agonist and orchiectomy	10	TT: RIA FT: RIA and EqD		75		1.25 pg ml−1 (0.125 ng dl−1)	0.75 nmol l−1 (21.6 ng dl−1)
Regis et al.28 2017	LHRH agonist	126	TT: Chemiluminescent enzyme immunoassay FT: RIA	Morning (8 a.m.–10 a.m.)	71.9	6	Recommended below 1.7 pg ml−1 (0.17 ng dl−1)	Recommended below 20 ng dl−1
Morote et al.29 2005	LHRH agonist	135	RIA		73.0	42	128 patients below 1.7 pg ml−1 (0.17 ng dl−1)	116 patients below 50 ng dl−1
Levell et al.30 1987	Orchiectomy	44	Calculated FT		71.1	6	Mean±s.d.: 23±1.4 pmol l−1 (0.66±0.04 ng dl−1)
Levell et al.30 1987	Estrogen (stilbestrol/Estracyt)	28	Calculated FT		71.1	6	Mean±s.d.: 5.9±0.9 pmol l−1 (0.18±0.03 ng dl−1) dl−1

ADT: androgen deprivation therapy; LHRH: luteinizing hormone-releasing hormone; TT: total testosterone; FT: free testosterone; RIA: radioimmunoassay; EqD: equilibrium dialysis; s.d.: standard deviation