Start with tube 1 and collect at least 10 drops of cerebrospinal fluid (CSF) in each of the four plastic tubes. Tube 1 should be filled with the CSF from the manometer if feasible. If the CSF flow is excessively slow, have the patient cough or bear down (like in the Valsalva maneuver), or have an assistant press on the patient's abdomen intermittently to enhance the flow. The needle can also be turned 90 degrees so that the bevel faces cephalad.