Complete Blood Count (CBC): What You Need to Know About This Common Blood Test

The complete blood count (CBC) is a routine blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets. It provides your doctor with a broad picture of your overall health and can help detect many conditions, such as anemia, infections, and certain blood disorders.

The androstenedione test measures the amount of androstenedione in your blood. Androstenedione is a hormone produced mainly by your adrenal glands (located above your kidneys) and, in women, also by the ovaries. It serves as a building block for other important hormones like testosterone and estrogen.

Your doctor may order a CBC as part of a routine checkup, to look into symptoms like fatigue, weakness, fever, unusual bruising, or unexplained weight loss, or to monitor an ongoing condition. It is also commonly used before surgery and to check how your body is responding to certain medications or treatments.

Your healthcare provider may order this test if you have symptoms suggesting a hormonal imbalance, such as: irregular or absent menstrual periods, excessive hair growth (hirsutism), severe acne, infertility, early puberty in children, or signs of masculinization in women. It helps doctors evaluate how well your adrenal glands are working and check for conditions affecting hormone production.

The test is done with a simple blood draw. A healthcare professional will clean the skin on your arm, wrap a band around your upper arm, and insert a small needle into a vein, usually on the inside of your elbow. The sample is collected into a tube and sent to a laboratory, and the whole process usually takes only a few minutes.

A healthcare professional will draw a small blood sample from a vein in your arm. The sample is then sent to a laboratory where androstenedione levels are measured using a sensitive technique called liquid chromatography-tandem mass spectrometry (LC/MS/MS). This method provides accurate and reliable results.

In most cases, no special preparation is needed for a CBC, and you can eat and drink normally beforehand. If other tests that require fasting are being done at the same time, your doctor will let you know. It is a good idea to mention any medicines or supplements you take, and wearing a short-sleeved shirt can make the blood draw easier.

Follow your healthcare provider's instructions. You may need to fast (not eat or drink anything except water) for a certain period before the test. Tell your doctor about all medications you're taking, as some medicines can affect hormone levels. For women, the timing of the test may be related to the menstrual cycle.