BLOOD TESTS Blood tests help diagnose medical problems and monitor for side effects of treatment. A specially trained nurse or technician uses a needle to collect blood from a vein. The blood samples are collected in tubes that are sent to a laboratory to be closely examined. In some cases, a finger prick may give enough blood for a test. These tests are usually done at the time of diagnosis to rule out other diseases and serve as a baseline for your child. Blood tests are used throughout treatment to monitor for possible side effects and your child’s response to treatment. COMPLETE BLOOD COUNT
Blood is made up of plasma (the liquid part of the blood) and cells floating in the plasma. There are three types of blood cells: white blood cells, red blood cells, and platelets. The white blood cells fight infection as part of the body’s immune system. The red blood cells carry oxygen throughout the body. The platelets stop bleeding by rushing to the site of an injury to form a clot. A complete blood count, or CBC, is a blood test that measures the amount and health of these three types of cells. The CBC is useful in diagnosing blood disorders. It also is used to diagnose cancers of the blood system, such as leukemia. Your child’s CBC results may change with each test because of other things going on in the body, such as infections or nutritional problems, or in response to medications like chemotherapy. BLOOD CHEMISTRY A blood chemistry test measures the balance of fluid, electrolytes, and blood sugar. These measurements can provide information about the health and function of the kidneys and liver and about the body’s metabolism; they can also help diagnose certain diseases, such as diabetes. They can indicate how a disease is responding to treatment and monitor for possible side effects. Blood chemistry tests may be done to: • Measure creatinine and blood urea nitrogen (BUN) to monitor changes in kidney function • Detect changes in liver function by measuring bilirubin • Measure erythrocyte sedimentation rate (ESR) and levels of C-reactive protein (CRP), which are sometimes elevated by certain cancers BLOOD CULTURE Blood may be drawn for a blood culture if there is a suspected bacterial infection in your child’s blood. Laboratory staff observes the blood over time to see if bacteria grow. The blood culture can confirm a bacterial infection and give important information about the type of bacteria involved to help the medical team A lumbar puncture is a procedure done to obtain a small sample of cerebral spinal fluid (CSF), which is the fluid that surrounds and protects our brain and spinal cord. CSF is made continually by our bodies, so the small amount removed is quickly replaced. This test is done to determine if any cancer cells have spread to the brain or spinal cord or if there is an infection in the central nervous system. In a lumbar puncture, also referred to as a spinal tap, a needle is inserted into the back between the spaces of the spinal bones (vertebrae) to obtain a sample of CSF. The needle enters the spinal column below the spinal cord to avoid injuring the cord. This test can be uncomfortable, so some children are sedated to help them lie still. If a bone marrow biopsy is ordered or due at the same time as the lumbar puncture, these procedures will be done together to limit your child’s exposure to sedation. determine how to treat it. LUMBAR PUNCTURE
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