Complete Blood Count (CBC) Test

The complete blood count, or CBC, is a routine blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets. It gives your doctor a broad picture of your overall health and can help detect a wide range of conditions, from infections and anemia to blood disorders.

The bedaquiline test measures how much of the antibiotic medication called bedaquiline is present in your blood serum or plasma. Bedaquiline is a specialized antibiotic used to treat multidrug-resistant tuberculosis (MDR-TB), which is a serious form of tuberculosis that does not respond to standard TB medications. This test is part of therapeutic drug monitoring, which means your healthcare team is checking to make sure you have the right amount of medicine in your body—not too little (which could make treatment ineffective) and not too much (which could cause side effects).

This test may be ordered as part of a routine checkup, to help diagnose symptoms such as fatigue, weakness, fever, or unusual bruising, to monitor an ongoing condition like anemia or infection, or to see how treatments such as chemotherapy are affecting your blood cells over time.

Your doctor may order this test for several important reasons. First, it helps confirm that the amount of bedaquiline in your blood is sufficient to fight the tuberculosis bacteria effectively. Second, it helps prevent potential side effects that can occur when drug levels become too high, such as liver problems or heart rhythm abnormalities. Third, it ensures that you are taking your medication correctly and that your body is absorbing it properly. Finally, this test may be used periodically throughout your treatment to monitor the drug levels and make any necessary adjustments to your dosage.

The test is done with a simple blood draw. A healthcare professional cleans the skin at the inside of your elbow, wraps a band around your upper arm, and inserts a small needle into a vein to collect a sample into a tube. The whole procedure usually takes only a few minutes.

A healthcare professional will draw a small sample of blood from a vein in your arm, typically in the morning before you take your daily dose of bedaquiline. This timing is important because it measures the lowest level of the drug in your system (called the "trough" level), which helps your doctor accurately assess whether your current dosage is appropriate. The blood sample is then sent to a laboratory where special equipment measures the concentration of bedaquiline. The results are usually available within a few days.

Results are compared with normal reference ranges. A low red blood cell count may suggest anemia, a high white blood cell count can point to infection or inflammation, and low platelets may affect clotting. Abnormal values do not always mean a serious problem, so your doctor will interpret them together with your symptoms and may order follow-up testing.

Your test results will show the concentration of bedaquiline in your blood. Your doctor will interpret these results based on your specific situation, including how far along you are in your treatment, your overall health, and other medications you may be taking. If your level is too low, your doctor may need to increase your dose or check that you are taking your medication properly. If your level is too high, your doctor may reduce your dose to prevent side effects. It is important to remember that the "normal" range can vary, and your doctor is the best person to explain what your specific results mean for your treatment.

This test is very safe. You may feel a brief sting when the needle goes in, and some people have mild soreness, bruising, or slight bleeding at the puncture site afterward. Serious problems such as infection or heavy bleeding are rare, but tell your care team if you take blood thinners or bleed easily.

The risks associated with this blood test are minimal and similar to any routine blood draw. You may experience slight bruising, bleeding, or soreness at the puncture site. In rare cases, fainting or infection may occur. The test itself does not carry any risks related to the medication bedaquiline—it simply measures what is already in your blood. If you have any concerns about the blood draw or about taking bedaquiline, discuss them with your healthcare provider before the test.