How to Take a Testosterone Test

Testosterone measurement is mainly done through blood tests and can be divided into three types: total testosterone, free testosterone and bioavailable testosterone. Before testing, you need to pay attention to fasting, avoid strenuous exercise, and choose a suitable time period.

1. Test items

Total testosterone is the part in the blood that is bound to sex hormone binding globulin and albumin. Free testosterone can act directly without being bound to any protein. Bioavailable testosterone includes free testosterone and the part loosely bound to albumin. Clinically, it is usually recommended to select total testosterone testing for the first screening. If the results are abnormal, free testosterone or bioavailable testosterone testing should be supplemented.

2. Test preparation

You should keep fasting for 8-12 hours before blood collection to avoid high-fat diet affecting the test results. No strenuous exercise is allowed on the day of the test. Those with higher cortisol levels in the morning are advised to postpone the test until after 10 a.m. People who take androgens or related drugs for a long time need to inform their doctor in advance.

3. Detection time

Healthy men should be tested between 8-10 a.m. in the morning, when testosterone levels are at their daily peak. Middle-aged and elderly men or those suspected of hypogonadism can choose to test at any time. Women who need testing should do it on days 3-5 of their menstrual cycle.

4. Detection method

The commonly used chemiluminescence method has high sensitivity and specificity, and the radioimmunoassay method is being gradually phased out. Some special tests require liquid chromatography-tandem mass spectrometry. The reference intervals of different laboratories may be different, so it is recommended to choose the same institution for reexamination.

5. Report interpretation

The normal reference range for total testosterone in adult men is generally 2.8-8.8 ng/ml. If it is lower than 2.8 ng/ml, it may indicate hypogonadism. The normal value of total testosterone in women usually does not exceed 0.75 ng/ml. Clinical diagnosis requires comprehensive judgment combined with gonadotropin and other indicators.

You should maintain a regular schedule before and after the test to avoid staying up late and being overtired. It is recommended for obese people to perform weight management before rechecking, because adipose tissue will promote the conversion of testosterone into estrogen. If the results are abnormal, the doctor may recommend a reexamination or further testing such as a pituitary MRI. Daily strength training and zinc supplementation can be used to maintain stable testosterone levels.