Complete Blood Count (CBC): What to Expect From This Common Blood Test

This test is a complete blood count, commonly called a CBC, a routine blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets. It gives your healthcare provider a snapshot of your overall health and can help detect conditions such as anemia, infection, and clotting or bleeding disorders.

The Nuclear Antibody (ANA) test is a blood test that detects antinuclear antibodies (ANAs) in your serum. Normally, your immune system produces antibodies to fight foreign invaders like viruses and bacteria. However, in some people, the immune system mistakenly creates antibodies that target the nucleus of the body's own cells—this is called an autoimmune response. This test uses a special laboratory method called immunofluorescence with rat kidney tissue to detect these abnormal antibodies.

The test is performed by drawing a small sample of blood, usually from a vein in your arm. A lab professional will clean the site, wrap a band around your upper arm, and insert a thin needle to collect the blood into a vial. The sample is then sent to a laboratory for analysis, and the entire process typically takes only a few minutes.

A healthcare professional will draw a small blood sample from a vein in your arm. This sample is sent to a laboratory where technicians mix it with rat kidney tissue. If antinuclear antibodies are present in your blood, they will bind to the kidney tissue. A fluorescent dye is then applied, and the tissue is examined under a special microscope. If the antibodies are present, they will glow (fluoresce), indicating a positive result.

You might need this test as part of a routine health checkup, or to help investigate symptoms such as fatigue, weakness, fever, unexplained bruising, or weight loss. It is also used to monitor chronic conditions, check how treatments like chemotherapy are affecting your body, and evaluate your response to infection or inflammation.

Your doctor may order this test if you have symptoms of an autoimmune disorder, such as joint pain, fatigue, fever, skin rashes, or muscle weakness. It is commonly used to help diagnose conditions like systemic lupus erythematosus (SLE), rheumatoid arthritis, scleroderma, polymyositis, and Sjögren's syndrome. The test may also be repeated over time to monitor disease activity.

In most cases, no special preparation is needed, and you can eat and drink normally before the test. Be sure to tell your provider about any medications, vitamins, or supplements you take, since some can affect the results. Drinking plenty of water beforehand can make your veins easier to find, and wearing a short-sleeved shirt may help.

No special preparation is typically required for this test. You can eat and drink normally before having your blood drawn. However, it is important to inform your doctor about any medications, supplements, or herbal remedies you are taking, as some drugs can affect test results. Also, let your doctor know if you have any existing autoimmune conditions or a family history of autoimmune diseases.