When collecting fluid during a lumbar puncture
, we don't exactly count drops of fluid.
Rather, we count CCs (cubic centimenters). Typically there are 4 tubes. We collect only 1-2 cc in the first and 2-6 in the rest. The amount collected depends on the purpose of the lumbar puncture. Decreasing fluid pressure, having enough fluid for many lab tests are 2 reasons to draw off larger amounts.