What is the test for inadmissible gunshot residue evidence in a civil case?

According to defendant, the basis of the gunshot residue evidencethe collection methodwas so unreliable as to make the evidence inadmissible pursuant to Evidence Code section 801. (See People v. Boyette (2002) 29 Cal.4th 381, 449 [" 'any material that forms the basis of an expert's opinion testimony must be reliable' "].) He points out that the gunshot residue sample was collected about six hours after the incident, after defendant had been handcuffed and placed in the back of a police car by an officer who had recently handled a firearm.