TRT monitoring: blood testing during testosterone therapy

TRT, short for testosterone replacement therapy, brings a testosterone deficiency back to a normal level. It is also called testosterone therapy.

Testosterone is a prescription medicine. You get it as an injection, gel or patch, always through a doctor. The aim is a healthy range, not the highest possible value.

That makes it different from a steroid cycle. In a cycle the doses sit far above what your body makes itself.

Guidelines only speak of a deficiency with symptoms and a repeatedly low testosterone value. That value is measured in the morning, on at least two separate days.

Symptoms that fit a deficiency include lower sex drive, fewer morning erections and low energy. One low result is not enough, because testosterone varies over the day.

No diagnosis yet? Then the hormone blood test is a more logical starting point than this panel. Discuss your results with your GP afterwards.

Yes, but only on a doctor's prescription. Your GP can test you and, if needed, refer you to a urologist or internist. There are also private TRT clinics in the Netherlands.

Whichever route you take, TRT treatment needs regular blood checks. That is what this test is for.

The therapy changes more than your testosterone. The best-known change is a rising hematocrit. Your body makes more red blood cells and your blood gets thicker.

Your own testosterone production also drops, and with it usually your sperm production. Your PSA can rise slightly. In some men estradiol rises too.

You discuss the pros and cons with your doctor. Guidelines list a hematocrit that runs too high, acne, fluid retention and tender breasts, among others. Sperm production also falls, which matters if you still want children.

Many of those effects show up in your blood first. That is why guidelines ask for regular checks during treatment.

This panel measures the seven values that matter most during therapy:

• Total testosterone: all the testosterone in your blood.
• Free testosterone: the part your body can use directly. It is calculated from testosterone, SHBG and albumin.
• SHBG: the protein that binds testosterone.
• Albumin: a blood protein that also counts toward your free testosterone.
• Hemoglobin: the oxygen-carrying protein in your red blood cells.
• Hematocrit: the share of red blood cells in your blood. Testosterone therapy can raise it.
• PSA: a prostate value that is followed periodically during treatment.

Guidelines do not recommend them for routine checks with injections or gel. Liver enzymes matter mainly with oral androgens. Cholesterol belongs to your general heart and vascular care.

Estradiol is usually measured only with symptoms, such as tender breasts. That way you do not pay for tests you do not need. If your doctor wants extra values, you add them separately.

Guidelines name a check three to six months after starting or after a dose change. After that, a yearly check is usual. Your doctor sets your schedule.

Timing matters too. With injections you measure midway between two injections. With gel you measure two to eight hours after applying it.

This TRT monitoring suits men who want to follow their therapy with their own numbers:

• Men treated at a clinic in the Netherlands or abroad
• Men who have used testosterone therapy for a while and want to measure periodically
• Men who want to keep following their hematocrit
• Men who want an extra measurement between two clinic checks

This test does not replace your doctor's care. It adds an independent measurement to it.

You order online, without a GP referral. After you order, we arrange your referral through ZorgDomein. Allow one business day. Orders placed in the evening or at the weekend start on the next business day.

The ZorgDomein email carries a barcode. Without a BSN there is no barcode: you then print your referral form through the link in the email and bring it to the draw location. You show it at one of the 650+ collection points, with a valid ID. Your order confirmation is not a referral.

You see for each value whether it falls within the reference range. A value outside that range does not automatically mean something is wrong.

A doctor looks at the whole picture: your testosterone together with your hematocrit. You follow your PSA for your prostate, especially from forty onward. Measure more often and you see your own trend.

Your results are usually in your account within a few business days. A BIG-registered doctor assesses every result. Discuss abnormal values and treatment decisions with your treating doctor.

Want to measure more broadly? Take a look at the extended blood test with 44 values.