Table 4.

Intraclass correlation coefficients of repeated serum measures of reproductive hormones in men (27 men, 76 serum samples).

Hormones	ICCa	ICCb
Total T (ng/dl)	0.47	0.50
Free T (pg/ml)	0.38	0.41
Inhibin-B (pg/mL)	0.85	0.89
FSH (IU/L)	0.98	0.98
LH (U/L)	0.71	0.71
Prolactin (ng/mL)	0.54	0.49
SHBG (nmol/L)	0.91	0.92
Inhibin-B/FSH ratio	0.93	0.93
FAI	0.65	0.66

Abbreviations: FAI: free androgen index, FSH: follicular stimulating hormone, ICC: intraclass correlation coefficient, LH: luteinizing hormone, SHBG: sex hormone binding globulin, T: testosterone.

Definitions: Y_ij represents the RH level of the ith participant at the jth sampling round. βo is the fixed effect intercept, β1 is the effect on the RH of a unit change in blood collection time, b_i is the random intercept of the i_th individual, and ε_ij is the random error.

^aModel: Y_ij = βo + b_i + ε_ij.

^bModel: Y_ij = βo + β1 Blood collection time_ij + b_i + ε_i.