N.J. Admin. Code § 13:71-14.32
A claimant may request, via indication on the claim form, a post-race blood and urine test be taken in full compliance with Subchapter 23 from any horse he or she claims in a race. The cost of testing pursuant to this section shall be set by the New Jersey Racing Commission and shall be paid by the claimant along with the claiming fee and applicable New Jersey sales tax. Should the test result in a positive finding, the claimant has the right to void the claim within 24 hours from the time notification of the positive finding was communicated to the claimant. The trainer at the time of entry into the claiming race shall be responsible for a positive finding of any drug and/or substance foreign to the natural horse. A claimant's election to conduct post-race testing shall not otherwise affect the transfer of ownership title pursuant to 13:71-14.17. Should the claimant not elect to conduct post-race testing, the former trainer shall conduct the horse to the detention barn after the race and the transfer of possession will occur as soon as is practicable. Should the claimed horse be selected for testing by the Commission, the cost of testing will remain the responsibility of the Commission, regardless of the claimant's indication that he or she wished to have the horse tested. The claimant shall have the right to void his or her claim should the forensic analysis of the sample so taken be positive for any drug and/or substance foreign to the horse.
N.J. Admin. Code § 13:71-14.32