First, no one knows the number of kits nationwide that have not been submitted for testing. Most kits that have not been tested are in police custody, not in crime labs, and there is no national estimate of these unsubommitted kits. Second, little is known about the age of unsubmitted kits. This is significant, because older unsubmitted kits risk the degrading of evidence and the inaccessibility of witnesses and suspects. Third, submitting a kit to a crime lab does not mean the lab will obtain usable DNA. Not all kits contain biological evidence, which is necessary for obtaining DNA, and not all biological evidence yields usable DNA. Fourth, Even if the police already have a suspect, testing a kit can be useful for a number of reasons. DNA collected in cases with known suspects and entered into the national DNA database could link a suspect to other crimes. Fifth, the cost to test a sexual assault kit varies widely. Several factors affect the cost, including the nature and complexity of the evidence and the prices labs have negotiated with vendors.