This test checks to see whether an infection is caused by a bacterium or a virus. It can also tell which specific virus is causing your infection.
Viral infections can cause illnesses anywhere in the body, including the skin, digestive tract, urinary tract, brain, lungs, and eyes. These illnesses can range from minor problems to serious diseases.
Viral cultures are done in different ways, depending on your condition and the virus the doctor thinks you may have. You may need to give a sample of blood, urine, or bodily fluids. In general, your test sample will be treated in the lab to keep the cells alive and allow them to grow. After a certain period of time, your culture sample will be checked to see if viruses are growing.
You might have this test if your doctor needs to find out whether you have a medical problem caused by a virus. Viral infections include bronchitis, pneumonia, meningitis, and encephalitis.
Your doctor may also order tests using bodily fluids or tissue samples to look for:
The genetic material of the virus
Antibodies that your body has made against a virus
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.
Normal results are negative, meaning you don't have the virus in your body. Positive results mean that a virus grew in the culture and that you have a viral infection.
Depending on your illness and the type of virus that could be causing it, a health care provider may need a sample of:
Fluid from the back of your nose or throat
Fluid and cells from a skin rash
Some procedures require a blood sample. Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
Other tests require a sample of cerebrospinal fluid, which is taken through a lumbar puncture in your lower back. During this procedure, a health care provider puts a needle between the bones of your spine and draws out a sample of fluid. Risks from a lumbar puncture include discomfort while the needle is inserted, headache, infection, bleeding, and brain herniation, which is rare but life-threatening.
Providing a urine sample poses no risks.
Waiting too long after infection can affect your results. If you have a viral infection, a sample for the culture should be taken soon after you develop symptoms for the best chance of capturing viruses. The test may be less useful later in the illness.
You don't need to prepare for this test. But be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.