7
Figure Footnotes:
a
The lower limit of the normal TT harmonized to the Centers for Disease
Control and Prevention (CDC) standard in healthy nonobese young men
is 264 ng/dL (9.2 nmol/L). (Brambilla DJ, Matsumoto AM, Araujo AB,
McKinlay JB. The effect of diurnal variation on clinical measurement of
serum testosterone and other sex hormone levels in men. J Clin Endocrinol
Metab. 2009;94(3):907–913.) This limit could be used for TT assays that
are CDC certified. For laboratories that are not CDC certified and do not
participate in an accuracy-based quality control program, the reference range
may vary considerably depending on the assay and reference population used.
Using the lower limit of the range established in local laboratories may not
accurately identify men with hypogonadism.
b
FT should be measured by an equilibrium dialysis method or estimated
from total testosterone, SHBG, and albumin using a formula that accurately
reflects FT by equilibrium dialysis. A harmonized reference range for FT has
not been established, so reference ranges may vary considerably depending on
the specific equilibrium dialysis method or the algorithm used to calculate FT.
Therefore, until a harmonized reference range is established, the lower limits
established by the laboratory may be used.
c
Conditions in which measurement of FT concentration is recommended,
including those conditions that alter SHBG levels, are listed in Table 3.
d
TT may also be high in some conditions in which SHBG levels are high, such
as HIV disease or use of some anticonvulsants.
e
Potentially reversible functional causes of secondary hypogonadism are listed
in Table 1.
f
If there is clinical indication of hypopituitarism or sella abnormality on
imaging, evaluation of other pituitary hormones (e.g., free thyroxine, morning
cortisol and adrenocorticotropic hormone [ACTH] stimulation test if
clinical hypocortisolism is suspected) should be performed.
g
Perform pituitary imaging (magnetic resonance imaging ) to exclude
pituitary and/or hypothalamic tumor or infiltrative disease when severe
secondary hypogonadism [e.g., serum T <150 ng/dL (5.2 nmol/L)],
panhypopituitarism, persistent hyperprolactinemia, or symptoms or signs of
tumor mass effect (such as new-onset headache, visual impairment, or visual
field defect) are present. Computed tomography (CT) scan may be sufficient
if macroadenoma is suspected or to assess parasellar bone involvement.
