[Normality of serum thyroid hormones, thyroxine binding globulin and thyroid stimulating hormone concentrations in normal adult men (author's transl)].

The normality of serum thyroxine (T4), triiodothyronine (T3), reverse T3, thyroxine binding globulin (TBG) and thyroid stimulating hormone (TSH) concentrations were investigated by using normal probability paper. 107 healthy adult men (age 35-48) were carefully selected; their healthiness was evaluated by physical, biochemical and roentogenologic examinations as well as by intensive interview on their past history. All assays were simultaneously carried out. When each cumulative distribution was plotted on normal probability paper, the straight line was obtained in T4, T3 and TBG but in rT3 and TSH, the lineality was seen only when logarithmic normal probability paper was used. The normal ranges by conventional statistical calculation, i.e., mean +/-2 S.D. was compared with those obtained on normal probability paper. The normal ranges of T4, T3 and TBG agreed well each other, whereas in rT3 and TSH, normal ranges obtained on the probability paper shifted toward higher levels than those by statistical calculations. Thus, it is suggested that the normal ranges of rT3 and TSH should be defined either by statistical calculation of each result after logarithmic transformation or by using logarithmic probability paper.