Understanding Your Laboratory Test: A Patient Guide

This test is a laboratory analysis performed on a small sample of your blood or another body fluid. It measures specific substances in your body so your health care provider can check how well your organs are working, look for signs of disease, and gather important information about your overall health.

The 17-Hydroxyprogesterone (17-OHP) test measures the amount of a specific hormone in your blood after a stimulation test. This test involves collecting a blood sample, receiving an injection of adrenocorticotropic hormone (ACTH), and then having a second blood sample taken about 30-60 minutes later. The test helps doctors evaluate how well your adrenal glands are functioning and detect certain hormonal disorders.

Your doctor may order this test to help find the cause of symptoms you are experiencing, to screen for a medical condition before it causes problems, to confirm or rule out a diagnosis, or to monitor how well a current treatment is working. Repeat testing can also help track a chronic condition over time.

Your doctor may order this test if you or your child have symptoms of a hormonal imbalance, such as early puberty, irregular periods, excessive hair growth, or adrenal gland problems. It is most commonly used to diagnose congenital adrenal hyperplasia (CAH), a genetic condition that affects adrenal hormone production. The test may also help distinguish between different types of adrenal disorders.

Preparation depends on the type of test your provider ordered. You may be asked to fast for 8 to 12 hours, so avoid all food and drinks except water before your appointment. Keep taking your regular medicines unless your provider tells you otherwise, and mention any supplements you use, since some can affect results.

Follow your doctor's instructions carefully. You may need to fast (not eat or drink) for a certain period before the test. Inform your doctor about all medications you are taking, as some medicines can affect test results. For children, explain the procedure in a reassuring way to help reduce anxiety. The test involves a needle stick, so let the healthcare provider know if you or your child has a fear of needles.

During the test, a trained technician will clean your skin, wrap a snug band around your upper arm, and draw a small amount of blood from a vein, usually in your arm or hand. The entire process typically takes only a few minutes, and your sample is then sent to the laboratory for careful analysis.

First, a healthcare provider will draw blood from a vein in your arm (first specimen). Then, you will receive an injection of ACTH, a hormone that stimulates the adrenal glands. After waiting about 30-60 minutes, a second blood sample will be drawn (second specimen). The entire procedure usually takes 1-2 hours. You may experience mild discomfort during the blood draw, and the ACTH injection might cause temporary flushing or warmth.

This test is very safe, and serious complications are rare. You may feel a quick sting when the needle is inserted, and mild bruising, soreness, or slight bleeding at the puncture site can occur afterward. Rarely, infection or heavy bleeding may develop, so contact your provider if these symptoms appear or worsen.

The risks are minimal and similar to routine blood tests. You may experience slight pain, bruising, or bleeding at the injection site. In rare cases, some people may have an allergic reaction to the ACTH injection. Fainting can occasionally occur during or after the blood draw. The benefits of obtaining important diagnostic information generally outweigh these small risks.