CDS likely refers to the pelvic Cul De Sac. The pelvic cul de sac is the lower area of the pelvis or abdomen (the area framed by the lower portions of your pelvic bones.)
There is normally a small amount of fluid in this area. In the event of infections, ruptures, or conditions such as cysts or cancer, the amount of fluid can increase. That the fluid is free simply means it is not inside a mass, cyst, or organ.
I would interpret the finding, "small free fluid" to possibly indicate the normal condition.
This site complies with the HONcode standard for trustworthy health information.
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. Med Help International, Inc. is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.