Why it is performed
- Assess symptoms compatible with androgen deficiency or excess.
- Investigate infertility with semen analysis and clinical assessment.
- Distinguish testicular from pituitary or hypothalamic causes.
- Monitor treatment when indicated.
How it is performed
Testosterone should ideally be measured in the morning and a low result is generally confirmed on another sample. LH and FSH help localise the cause; SHBG improves interpretation of the free fraction.
Preparation
- Attend between 7 and 10 a.m. for testosterone where possible.
- Report night-shift work, acute illness, obesity, opioids, anabolic steroids and hormone treatment.
- Do not use testosterone or supplements without medical supervision.
- Diagnosis requires symptoms plus repeatedly low levels.
How Askabide processes it
Combined pathway
Testosterone, LH, FSH, prolactin or TSH may be processed on ichroma II when cartridges are active and validated. SHBG, measured free testosterone and other studies may be referred.
Part is performed at Askabide and another phase or confirmation is processed externally.
Results and indicative intervals
Intervals vary by method, analyser, reagent, units, age, sex, pregnancy, menstrual-cycle phase and reference population. The valid interval is the one printed on the laboratory report.
| Parameter or result | Indicative reference | How it is interpreted |
|---|---|---|
| Morning total testosterone | ≈300–1000 ng/dL | The lower limit depends on method and should be confirmed if low. |
| LH | ≈1,7–8,6 UI/L | High with low testosterone suggests testicular failure; low or inappropriately normal may suggest a central cause. |
| FSH | ≈1,5–12,4 UI/L | May rise with impaired spermatogenesis. |
| Prolactin | ≈4–15 ng/mL | Range is method-dependent; stress and medicines may raise it. |
| SHBG | Age- and method-dependent | Changes the relationship between total and free testosterone. |
Important limitations
- Low testosterone during acute illness is insufficient to diagnose hypogonadism.
- Obesity and low SHBG may lower total testosterone without the same fall in free testosterone.
- Infertility requires semen analysis; hormones do not replace it.
- Testosterone treatment may reduce fertility.