Complete Blood Count (CBC) Test: What It Is, How It Is Done, and What Your Results Mean

A complete blood count, or CBC, is a common blood test that measures the different cells in your blood, including red blood cells, white blood cells, platelets, hemoglobin, and hematocrit. It gives your healthcare provider a broad picture of your overall health and can help detect a wide range of conditions.

A nose bacteria culture, also called a nasal culture or aerobic nasal culture, is a laboratory test that collects a sample from your nasal passages to identify and grow bacteria. The sample is placed in a special environment that allows aerobic bacteria (bacteria that need oxygen to grow) to multiply, making them easier to identify under a microscope.

The sample is collected through a simple blood draw. A healthcare professional will clean the skin on the inside of your elbow, place a snug band around your upper arm, and insert a small needle into a vein to collect blood into a tube. The procedure usually takes only a few minutes, and you may feel a quick pinch or sting.

A healthcare provider will use a sterile swab to collect a sample from inside your nostril. The swab is gently inserted into your nasal passage, rotated to collect mucus and cells, then placed in a sterile container and sent to the laboratory for analysis.

Your provider may order this test as part of a routine checkup, to investigate symptoms such as fatigue, weakness, fever, bruising, or unexplained bleeding, to monitor a known condition like anemia or infection, or to track how treatments such as chemotherapy or certain medications are affecting your blood cells.

Your doctor may order this test if you have symptoms of a nasal or sinus infection, such as persistent nasal congestion, facial pain, discharge from the nose, or suspected bacterial sinusitis. It is also used for patients at risk of serious bacterial infections, such as those preparing for surgery or with weakened immune systems.

Results are compared with standard reference ranges. Values that are higher or lower than normal can point to conditions such as anemia, infection, inflammation, clotting problems, or blood disorders. Many mild abnormalities have simple explanations, so your provider will interpret your numbers together with your symptoms, medical history, and other test results before recommending next steps.

Results will show whether bacteria were found in your nasal sample. If bacteria grow, the lab will identify the specific type. A positive result means you have a bacterial infection, while a negative result may indicate a viral infection, no infection, or that the sample was collected improperly. Common bacteria found include Staphylococcus aureus (including MRSA), Streptococcus pneumoniae, and Haemophilus influenzae.