To interpret your lumbar puncture results, you must first be aware of the normal values assigned to cerebrospinal fluid (CSF), which can differ with each laboratory. This means you should find out the normal values that your laboratory assigned to CSF so you can interpret your lumbar puncture results accordingly. In general, though, lumbar puncture results are either normal or abnormal, and if abnormal, there can be an array of causes. Various values measured in a lumbar puncture include the CSF appearance, pressure and total protein, as well as glucose, cell count and the presence of microorganisms or cancer cells. Your doctor will be able to diagnose any condition you might have, based upon his evaluation of all the values combined.
Normal CSF is usually clear and colorless in appearance, and if your lumbar puncture results show that your CSF is cloudy or colored, this is abnormal. In general, cloudy CSF can be an indication of an infection, or an increase in protein or white blood cells. Red CSF signals bleeding, or obstruction of the spinal cord. Other colored CSF, such as brown, orange or yellow, is a sign of previous bleeding or an increase in protein. In some cases, the lumbar puncture procedure itself causes blood to show up on the results, which makes for a confusing diagnosis.
Abnormal lumbar puncture results of CSF pressure, protein and glucose are either decreased or increased values measured in relationship to normal values assigned by the laboratory conducting the test. Decreased CSF pressure can be due to a variety of conditions including fainting, shock or a tumor in the skull; increased pressure, on the other hand, indicates an increase of the pressure inside the skull. With CSF total protein, decreased value is a sign that there is a rapid production of CSF occurring — an increased value of protein signals various different conditions such as blood in the fluid, diabetes or infections. Decreased measurement of glucose indicates bacterial or fungal infections, as well as hypoglycemia, while increased glucose is suggests high blood pressure.
Your lumbar puncture results might also measure your CSF cell count. In CSF, there are only white blood cells. An increase in white blood cell count, though, can signal a variety of conditions, including abscess, infection and stroke. There should not be any red blood cells in CSF, so the presence of any red blood cells indicates bleeding. In some cases, the bleeding can be a result of the lumbar puncture procedure itself.
Additional values you might see in your lumbar puncture results are the presence of any cancer cells or microorganisms. Normal CSF does not contain any cancer cells or microorganisms, so the presence of any indicates an abnormal result. If there are cancer cells present, this means there could be cancer in the brain, CSF or spinal cord. Microorganisms, which include bacteria, fungi and viruses, are a sign of a disease or infection.