Name of the Procedure:

Testosterone; bioavailable, direct measurement (e.g., differential precipitation)

Summary

This blood test measures the amount of bioavailable testosterone in your body, which is testosterone available to tissues. Bioavailable testosterone includes free testosterone and testosterone that is loosely bound to proteins.

Purpose

The test is performed to evaluate testosterone levels to diagnose or monitor conditions related to hormone imbalances, such as male hypogonadism, andropause, and certain tumors. The goal is to determine if testosterone levels are within the normal range or if there is a deficiency or excess.

Indications

• Symptoms of low testosterone: fatigue, low libido, depression, reduced muscle mass.
• Symptoms of high testosterone: excessive hair growth, acne, mood swings.
• Suspected hormone imbalances.
• Monitoring testosterone levels in individuals receiving testosterone therapy.
• Investigation of infertility in men.

Preparation

• Fasting may not be necessary, but it is best to follow your doctor's instructions.
• Avoid taking testosterone supplements or medications that could affect the test results as per your doctor's advice.
• The test is usually scheduled in the morning when testosterone levels are highest.

Procedure Description

1. A healthcare provider will clean the area inside your elbow or the back of your hand with an antiseptic.
2. A tourniquet is applied to your upper arm to make the veins more prominent.
3. Blood is drawn from a vein using a needle.
4. The sample is collected into a vial or tube for analysis.
5. Laboratory techniques such as differential precipitation are used to separate bioavailable testosterone from other forms of testosterone in the blood.

Duration

The blood draw typically takes about 5-10 minutes. Laboratory analysis may take a few days to a week.

Setting

The procedure is commonly performed in a hospital, outpatient clinic, or diagnostic laboratory.

Personnel

• Phlebotomist or a nurse to draw the blood.
• Laboratory technicians/clinical pathologists to analyze the blood sample.

Risks and Complications

• Minor bruising or discomfort at the blood draw site.
• Rarely, infection at the injection site.
• Fainting or dizziness in some patients.

Benefits

• Provides precise measurement of bioavailable testosterone levels.
• Helps in diagnosing and managing conditions related to testosterone imbalance.
• Can guide effective treatment plans for hormone therapy.

Recovery

• Minimal recovery time; patients can typically return to normal activities immediately.
• Bandage or cotton ball is applied to the puncture site to stop any bleeding.

Alternatives

• Total testosterone test: measures all testosterone in the blood but not as specific as bioavailable testosterone.
• Free testosterone test: measures only the testosterone not bound to proteins.
• Clinical evaluation of symptoms without a blood test.

Patient Experience

• The patient may feel a slight pinch or sting when the needle is inserted.
• Some people may feel nervous about blood draws, but discomfort is generally minimal.
• Follow-up appointments may be needed to discuss results and next steps for treatment. Pain management and comfort measures are typically not necessary due to the minimally invasive nature of the test.