Studies show that a total testosterone less than 5.0 nmol/L is
rarely associated with serious pathology. Levels above 5.0
nmol/L may indicate a serious ovarian or adrenal disorder, but
are also seen in some cases of PCOS. In such cases, raised androstenedione
and raised DHEA-S suggest
adrenal involvement, whereas increased androstenedione and
normal DHEA-S suggest ovarian pathology.
Male: Please note diurnal
rhythm: levels are highest at 7–11am and lowest around 6.00pm.
Levels decrease with age (due
to decrease in SHBG) and some normal men will have
levels at the lower end of the reference range. Eating may
transiently lower testosterone levels. If a patient
has a low result the test should be repeated on a 9 a.m. fasting sample. Patients with
testicular failure will have low testosterone levels with
raised LH and FSH levels.
levels may be low in erectile dysfunction BUT do not correlate
with erectile dysfunction (or impotence / libido) i.e. may have