In the case of Bullcoming v. New Mexico, 131 S.Ct. 2705 (2011) the United States Supreme Court recently held that a lab report in a drunk driving case is not admissible on its own.  In other words, if a person is charged with DWI, the prosecutor cannot simply show the judge the lab report and get a conviction.  The state has the burden of calling the analyst as a witness who must testify as to the laboratory procedures, the tests performed, and the results of the tests.  The Court stated:

The Sixth Amendment’s Confrontation Clause gives the accused “[in all criminal prosecutions, . . . the right . . . to be confronted with the witnesses against him.” In Crawford v. Washington, 541 U. S. 36, 59, this Court held that the Clause permits admission of “[testimonial statements of witnesses absent from trial . . . only where the declarant is unavailable, and only where the defendant has had a prior opportunity to cross-examine.” Later, in Melendez-Diaz v. Massachusetts, 557 U. S. ___, the Court declined to create a “forensic evidence” exception to Crawford, holding that a forensic laboratory report, created specifically to serve as evidence in a criminal proceeding, ranked as “testimonial” for Confrontation Clause purposes. Absent stipulation, the Court ruled, the prosecution may not introduce such a report without offering a live witness competent to testify to the truth of the report’s statements.

The Confrontation Clause, the opinion concludes, does not permit the prosecution to introduce a forensic laboratory report containing a testimonial certification, made in order to prove a fact at a criminal trial, through the in-court testimony of an analyst who did not sign the certification or personally perform or observe the performance of the test reported in the certification. 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.