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Testosterone, Total

Source Blood
Mnemonic TESTO
Specimen Requirements

1 x 3 mL or 4.5 mL light green (mint) top PST tube. Gold top SST tube also acceptable.

0.5 mL plasma or serum

Minimum Whole Blood Volumes for Microcollections

Specimen Handling
Additional Information Indicate gender of patient on the requisition.

Testosterone exhibits diurnal variation in adult males. Values are highest in the morning, with decreases up to 25% later in the day. Reference intervals were established on specimens collected in the morning (07:00 - 10:00), thus it is suggested to collect specimens within this timeframe. The amplitude of diurnal variation decreases with age, with patients aged >70 showing an approximate 10% decrease.
Diurnal variation of testosterone in females is not well defined in the literature, but similar variation may be expected in pre-menopausal women.
Reference:
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.
Testing Location Chemistry-DSC
Testing Frequency Daily
Alternate Name(s)
Reference Interval
Age Male Female Units

1 day - 9 years

0.0 - 1.0

0.0 - 1.0

nmol/L

10 years - 17 years, Tanner Stage 1 0.0 - 1.0  0.0 - 1.0 nmol/L

10 years - 17 years, Tanner Stage 2

0.0 - 15.0

0.0 - 1.0

nmol/L

10 years - 17 years, Tanner Stage 3 2.2 - 27.0 0.0 - 1.0  nmol/L
10 years - 17 years, Tanner Stage 4 6.2 - 26.5 0.0 - 1.0 nmol/L
10 years - 17 years, Tanner Stage 5 6.5 - 29.0 0.2 - 1.3 nmol/L
18 years - 150 years 8.0 - 29.0 0.5 - 2.0 nmol/L