Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Testosterone is the major androgen in males and is controlled by luteinising hormone (LH). LH is released from the anterior pituitary exerting the primary control on testosterone production and acting directly on the Leydig cells in the testes. Testosterone stimulates adult maturation of external genitalia and secondary sex organs, and the growth of beard, axillary and pubic hair. It has anabolic effects leading to increased linear growth, nitrogen retention and muscular development. Testosterone strongly binds to plasma proteins such as sex hormone-binding globulin (SHBG). It also binds with low affinity to cortisol binding globulin (CBG) and albumin.
Measurement of serum testosterone, along with serum LH/FSH, assists in evaluation of hypogonadal males. Testosterone concentrations are much lower in females compared to males. The major sources of testosterone in females are the ovaries, the adrenal glands and the peripheral conversion of precursors, specifically the conversion of androstenedione to testosterone. Measurement of testosterone is important in the investigation of hirsuitism and menstrual irregularities in women.
Specimen container paediatric:
Serum (SST or plain tube)
Specimen container adult:
Serum (SST or plain tube)
Minimum volume paediatric:
0.5 mL
Minimum volume adult:
1 mL
Sample stability:
Unseparated sample: 24 hours
Separated sample: unknown at 15-25°C, 7 days at 2-8°C, 6 months at -20°C
Transport requirements:
Ambient
Interpretation:
Low testosterone concentrations in men may indicate hypogonadism. Further investigations (such as LH/FSH) are required to distinguish primary from secondary causes. Elevated plasma testosterone in women indicates hyperandrogenism which may be due to disorders such as polycystic ovarian syndrome (PCOS), ovarian/adrenal tumours or congenital adrenal hyperplasia.
Reference ranges:
Male:
Up to 18 years: See Tanner stages below.
18 to 49 years: 8.6 – 29 nmol/L
50 years and over: 6.7 – 25.7 nmol/L
Male Tanner Stages (7-18 years):
Stage 1: <1.0 nmol/L
Stage 2: <15.0 nmol/L
Stage 3: 2.3 – 27.0 nmol/L
Stage 4: 6.2 – 26.5 nmol/L
Stage 5: 6.5 – 30.6 nmol/L
Female:
Up to 18 years: See Tanner stages below.
18 to 49 years: 0 – 1.7 nmol/L
50 years and over: 0 – 1.4 nmol/L
Female Tanner Stages (7-18 years):
Stage 1: <1.0 nmol/L
Stage 2: <1.0 nmol/L
Stage 3: <1.0 nmol/L
Stage 4: <1.0 nmol/L
Stage 5: <1.3 nmol/L
Free Testosterone:
Male:
Up to 18 years: No information available
18 to 49 years: 198 – 619 pmol/L
50 years and over: 163 – 473 pmol/L
Female:
Up to 18 years: No information available
18 to 49 years: 3 – 33 pmol/L
50 years and over: 1 – 20 pmol/L