A healthy 34-year-old full-term parturient was admitted to the labor suite where a combined spinal-epidural (CSE) was easily placed on the first attempt for labor analgesia. After an uneventful delivery, the epidural catheter was removed. Two days later, the patient experienced a fluid leak from the puncture site. The fluid was analyzed to determine whether it was an interstitial or a cerebrospinal fluid (CSF). We describe a novel technique to collect the leaking fluid without admixing fluid from the surrounding area. No previous reports describe a similar technique to diagnose the source of this questionable fluid leak.