The US Supreme Court has decided Bullcoming. Surrogate testimony is no good.
The question presented is whether the Confrontation Clause permits the prosecution to introduce a forensic laboratory report containing a testimonial certification—made for the purpose of proving a particular fact—through the in-court testimony of a scientist who did not sign the certification or perform or observe the test reported in the certification. We hold that surrogate testimony of that order does not meet the constitutional requirement. The accused’s right is to be confronted with the analyst who made the certification, unless that analyst is unavailable at trial, and the accused had an opportunity, pretrial, to cross-examine that particular scientist.
The US Supreme Court acknowledges what others refuse to acknowledge. There is the potential for human error, even when using GS/MS equipment. Slip op. at 4 (with footnotes [n.1] to support what we all know, or should know).
Justice Sotomayor in concurring posits some interesting examples of situations where M-D and Bullcoming may not apply.