Lab Information Manual

Laboratory:

Clinical Biochemistry (AUTOMATED)

Test Name:

TESTOSTERONE, TOTAL - (P)

Test Code: TST

Clinical Information:

Test Indications: TTestosterone levels are used for the assessment of individuals with clinical symptoms suggestive of androgen deficiency or excess, such as:

Evaluation of infants with ambiguous genitalia or virilization
Evaluation of boys with delayed or precocious puberty
Monitoring of testosterone replacement or antiandrogen therapy
Women with infertility, hirsutism, virilization or oligomenorrhea
Diagnosis of androgen-secreting tumors

Testosterone by immunoassay may be used to evaluate hypogonadism in males and to monitor testosterone hormone replacement therapies.

Free and bioavailable testosterone may provide additional information when protein-binding abnormalities are suspected: TESTOSTERONE TOTAL, BIOAVAILABLE and FREE (CALCULATED) - (S)

Low testosterone levels found in children, females and individuals on testosterone-suppressing hormone therapy may require follow-up testing by mass spectrometry: TESTOSTERONE, TOTAL & FREE - (S)

If test results are inconsistent with clinical picture, please contact Clinical Biochemist on-duty at 431-276-0131 (9am-4 pm, Monday to Friday excl Stat Holidays).

Recommendations: Endocrine Society Clinical Practice Guidelines recommend making a diagnosis of androgen deficiency only in men with consistent symptoms and unequivocally low serum testosterone levels. Morning (0700 - 1000h) fasting samples, collected on two or more occasions to minimize biological variability, are recommended for the assessment of male hypogonadism. The evaluation of androgen deficiency should not be made during an acute or subacute illness.
Endocrine Society Clinical Practice Guidelines recommend against screening for androgen deficiency in the general population. J. Clin Endocrinol Metab June 2010, 95 (6): 2536 – 2559

Patient preparation instructions: This test is unaffected by multivitamins (45 - 125 µg biotin) or biotin-only supplements (up to 140 ng/mL dose). Fasting is not required, but may be requested (8-12 h) by ordering physician – patients should follow their doctor’s instructions.

Collection Devices:

Preferred Device:	1 - Li Heparin Plasma Separator Tube(s) - Full Tube Collection Li Heparin Plasma Separator Tube(s) - Full Tube Collection Manufacturer: BD (Becton Dickinson) Catalogue #: 367962
Alternate Device:	1 - Microtainer(s) - Li Heparin PST (0.6mL) to fill line Microtainer(s) - Li Heparin PST (0.6mL) to fill line Manufacturer: Becton Dickinson & Company Catalogue #: 365987

Acceptable specimen include serum with or without gel and EDTA plasma

Specimen Required:

Plasma: 2.0 mL

Pediatric Plasma: 0.3 mL

Specimen Stability:
Ambient: 5 days
Refrigerated: 7 days
Frozen: 6 months, freeze only once.

Referral:

Serum: 2.0 mL

Samples must be transferred to an aliquot tube and stored/shipped frozen for all off-site testing (#110-10-05 Serum / Plasma Separation Procedure & Transport)

Requisition:

_SH Endocrinology (General) Primary Care Requisition (R250-10-76)

_SH Endocrinology (Specialist) Requisition (R250-10-77)

Reference Values:

	Age	Reference Interval nmol/L
Female	0 - <5 wk	0.7 – 2.2
	5 wk - <13 y	< 1.0
	≥13 y	0.5 – 2.4
Male	0 - <8 mo	2.6 – 14
	8 mo - <13 y	< 1.0
	≥13 y	9.7 - 38

Additional information:

	Female 5-95th percentile	Male 5-95th percentile
Tanner stage 1	≤ 0.4 nmol/L	≤ 0.4 nmol/L
Tanner stage 2	≤ 0.4 nmol/L	≤ 15.0 nmol/L
Tanner stage 3	≤ 0.8 nmol/L	2.3 – 27.0 nmol/L
Tanner stage 4	≤ 0.9 nmol/L	6.2 – 26.5 nmol/L
Tanner stage 5	≤ 1.3 nmol/L	6.5 – 30.6 nmol/L
20-49 y	≤ 1.7 nmol/L	8.6 – 29.0 nmol/L
≥50 y	≤ 1.4 nmol/L	6.7 – 25.7 nmol/L

Based on 6:30 am – 1:00 pm collection times
Method of Analysis: Roche electrochemiluminescence

Availability:

Daily