Pathology Handbook

Testosterone

Synonyms

Total testosterone

Clinical Indications

In females, testosterone is produced in the ovaries and adrenal glands and is primarily measured to exclude androgen excess as a result of adrenal or ovarian tumours. In males, testosterone is usually measured as a part of the investigation of ED/impotence/infertility or suspected hypopituitarism.

Request Form 

Request on ICE

Availability

On request. 

Specific Criteria

Assessment of androgen status.

Turnaround Time

Same Day (Monday to Friday)

Specimen

Serum

Volume

1 ml

Container

Vacutainer gold top

Collection

Male samples should be collected in the early morning as there is a significant diurnal variation in testosterone levels

Causes for Rejection

Unlabelled sample

Reference Range

. Testosterone (nmol/L)
Age Males Females
< 6 months Less than 6.0  < 0.2
6 months - 1yr < 0.2 < 0.2
1 - 5 years < 0.9 < 0.4
5 -7 years < 1.0 < 0.4
7 - 18 years See table below
18 - 49 years 8.6 - 29.0 0.3 -1.7
> 49 years 6.7 - 25.7 0.1 - 1.4

 

. Testosterone (nmol/L)
Tanner Stage Males (aged 7-18 yrs) Females (aged 8-18 yrs)
1 Less than 0.09 < 0.09 - 0.21
2 < 0.09 -15.0 < 0.09 - 0.36
3 2.3 -27.0 < 0.09 - 0.82
4 6.2 -26.5 < 0.09 - 0.93
5 6.5 - 30.6 0.16 - 1.33

  

Interpretation

Female

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 normal  DHEA-S suggest adrenal involvement, whereas increased androstenedione and normal DHEA-S suggest ovarian pathology.

Male

Levels decrease with age and some normal men will have levels at the lower end of the reference range.  There is diurnal variation and if a patient has a low result the test should be repeated on a 9 a.m. sample.  Patients with testicular failure will have low testosterone levels with raised LH and FSH levels.