NO. 2053-01







Per curiam. Keller, P.J., filed a concurring opinion. Johnson, J., filed a concurring opinion. Keasler, J., filed a dissenting opinion, joined by Hervey, J.


The present case involves the admissibility of scientific evidence under Texas Rule of Evidence 702 and Kelly v. State. (1) Specifically, we granted the State's following three grounds for review:

1) Must a party seeking to introduce evidence of a scientific principle always present evidence sufficient to satisfy the test of Kelly v. State, 824 S.W.2d 568 (Tex. Cr. App. 1992), regardless of the particular scientific principle?

2) Where either the Court of Criminal Appeals or a court of appeals has determined the validity of a particular scientific principle and a technique applying that principle, must a party subsequently seeking to introduce evidence based upon that scientific principle nevertheless satisfy the first two prongs of the test of Kelly v. State, 824 S.W.2d 568 (Tex. Cr. App. 1992)?

3) Did the Court of Appeals in this case err in holding that the trial court had abused its discretion by admitting evidence of the results of a urinalysis test of the appellant's urine sample?

The short answers to these three questions are: "No, no, and no." Therefore, we affirm the court of appeals which held that the trial court abused its discretion in revoking appellant's community supervision based upon scientific evidence that was not shown to be reliable. Hernandez v. State, 55 S.W.3d 701 (Tex. App. - Corpus Christi 2001).


Appellant pleaded guilty to possession of marijuana and the trial court placed him on probation for ten years. Almost a full ten years later, the State filed a motion to revoke his probation alleging, inter alia, that appellant failed to avoid the use of controlled substances and had tested positive for marijuana on January 28, 1999.

At the revocation hearing, Alonzo Perez, a laboratory technician, testified that he tested appellant's urine for the presence of drugs using a machine called an "ADx analyzer." The test results were positive. Mr. Perez testified that he had worked as a urinalysis lab technician for two and a half years. He explained that he had thirty-two hours of specialized training on the ADx analyzer and about two and a half weeks of extensive on-the-job training. When asked how many urinalysis tests he had performed, he replied, "I couldn't say. It's just so many."

On cross-examination, appellant asked Mr. Perez to explain the scientific theory underlying the test:

The machine uses what you call flourescence polarization amino acid technology which deals with antigens and antibodies that are in the blood system, and the antigens being the drugs .... Well, what the machine does is, you see, the antigens are in your bloodstream. That's the drugs, but they are not in our system long enough for your body to produce antibodies to attack them so what the company does is they send you reagins [sic] which you use which what they do is they inject lab rats with these drugs so they can produce the antibodies, and what happens is the antibodies attach to the antigens and then the drug machine and these antibodies have a flourescent tag on them and when the light is shown through that is what gives you the reading.

Mr. Perez testified that he had learned that the machine was ninety-five to ninety-six percent accurate, but he conceded that he did not know the technical aspects of the machine's operation.

At the close of evidence, appellant re-urged his Rule 702 objections to Mr. Perez's testimony and to the lab report. He argued that Mr. Perez "did not know anything about the scientific theory underlying the test, whether the scientific theory was valid, whether any techniques used in applying the theory [were] valid, whether or not the technique was properly applied in this case." The trial court, however, ruled that the evidence was reliable and noted that Mr. Perez had testified on this subject in other cases.

The Corpus Christi Court of Appeals held that Mr. Perez's testimony and the lab report were inadmissible because the State failed to satisfy the scientific reliability requirements set out in Kelly. (2) The court of appeals also noted that it had previously held Mr. Perez's testimony inadmissible for the same reason in an earlier, unpublished opinion involving this same appellant. (3)


A party seeking to introduce evidence of a scientific principle need not always present expert testimony, treatises, or other scientific material to satisfy the Kelly test. It is only at the dawn of judicial consideration of a particular type of forensic scientific evidence that trial courts must conduct full-blown "gatekeeping" hearings under Kelly. Once a scientific principle is generally accepted in the pertinent professional community and has been accepted in a sufficient number of trial courts through adversarial Daubert/Kelly hearings, subsequent courts may take judicial notice of the scientific validity (or invalidity) of that scientific theory based upon the process, materials, and evidence produced in those prior hearings. (4)

Similarly, once some courts have, through a Daubert/Kelly "gatekeeping" hearing, determined the scientific reliability and validity of a specific methodology to implement or test the particular scientific theory, other courts may take judicial notice of the reliability (or unreliability) of that particular methodology. (5)

Trial courts are not required to re-invent the scientific wheel in every trial. However, some trial court must actually examine and assess the reliability of the particular scientific wheel before other courts may ride along behind. Some court, somewhere, has to conduct an adversarial gatekeeping hearing to determine the reliability of the given scientific theory and its methodology. (6)

In this case, appellant objected under Rules 702-705 to the technician's testimony concerning the results produced by an ADx analyzer testing machine. Appellant did not argue that the underlying scientific theory of urinalysis, as a mode of determining whether a person has consumed a certain substance, is scientifically invalid. His objection went to the machine itself. He stated:

There has been no proper predicate to establish the ... reliability of the testing procedures and this gentleman has not been qualified as an expert. We don't know anything about the machine, whether it's reliable. Based on Rule 702 and Rule 705, I would object that this burden by the State has not been met, Your Honor.

The trial court simply stated:

The procedures meet the requirements of law. The Court has upheld the procedure in other cases that the witness Alonzo Perez testified to.

The fact that a trial court has allowed some type of scientific testimony by a particular witness before (perhaps without objection) does not mean that the witness' testimony is, ipso facto, scientifically reliable in this case. Nor does the fact that the trial court has allowed this witness to testify to these procedures before explain how or why the ADx machine is a scientifically reliable one for determining the presence of a controlled substance. It may well be scientifically reliable, but the trial court's statement that he has allowed this testimony before does not make it so. Perhaps the trial judge had previously conducted numerous Daubert/Kelly gatekeeping hearings on precisely this issue and had repeatedly found it scientifically reliable. If he had, then either the State or the trial judge should put that on the record along with materials from those previous hearings. (7) There is no other evidence or material in this trial record, however, that would support any finding of the scientific reliability of the ADx analyzer.

Thus, the Corpus Christi Court of Appeals did not err. It found that the trial court abused its discretion in admitting the results of "an ADX analyzer" without any showing of its scientific reliability or any reliance upon other scientific materials or judicial opinions which had found "an ADx analyzer" a reliable methodology for determining whether a person does or does not have marijuana in his body. (8)

In his brief to this Court, the State Prosecuting Attorney presents a plethora of cites to scientific articles and learned treatises, as well as to some cases from other jurisdictions concerning this general area of scientific endeavor. This is swell stuff. The trial court should have been given this material, and appellant should have been allowed an opportunity to cross-examine any witnesses who sponsored it. The trial court hearing is the main event for Daubert/Kelly gatekeeping hearings; it is not a try-out on the road to an appellate scientific seminar.

The State had the burden of proof at trial (or, as in this case, at the probation revocation hearing) to show, by clear and convincing evidence, that the ADx analyzer is a reliable method of determining the presence of marijuana in a person's body. (9) It failed to offer any testimony, any scientific material, or any published judicial opinions from which the trial court might take judicial notice of its scientific reliability. (10) It cannot now rely upon the appellate courts to become independent scientific sleuths to ferret out the appropriate scientific materials which could support the trial court's decision to allow the ADx technician's testimony. (11) Thus, the court of appeals was confronted with a trial record which did not support the scientific reliability of the ADx machine. (12) It cannot be faulted for concluding that, based upon the record before it, the State had failed to show the machine's reliability.

Although appellate courts may take judicial notice of other appellate opinions concerning a specific scientific theory or methodology in evaluating a trial judge's Daubert/Kelly "gatekeeping" decision, (13) judicial notice on appeal cannot serve as the sole source of support for a bare trial court record concerning scientific reliability.

Therefore, we affirm the judgment of the court of appeals.

Delivered: June 4, 2003


1. 824 S.W.2d 568 (Tex. Crim. App. 1992).

2. Hernandez, 55 S.W.3d at 705-06.

3. Id. at 706 ("in an earlier case involving this same appellant we held in an unpublished opinion that urinalysis test results produced by an ADX analyzer were not admissible") (emphasis in original).

4. See Weatherred v. State, 15 S.W.3d 540, 542 n.4 (Tex. Crim. App. 2000) ("once a particular type of scientific evidence is well established as reliable, a court may take judicial notice of that fact, thereby relieving the proponent of the burden of producing evidence on that question"); Emerson v. State, 880 S.W.2d 759, 764 (Tex. Crim. App. 1994); see also United States v. Jakobetz, 955 F.2d 786, 798-800 (2d Cir. 1992) (upholding admission of results of DNA profiling analysis after eight full days of hearings on the reliability of the RFLP analysis, the fixed-bin analysis, and the statistical interpretation of the proffered results; encouraging courts facing a similar issue in the future to take judicial notice of the general theories and specific techniques involved in DNA profiling). See generally Christopher B. Mueller & Laird C. Kirkpatrick, Federal Evidence 353 at 663 (2d ed. 1994). Professors Mueller and Kirkpatrick note that:

Commentators argued for years that the general acceptance standard [of Frye] is better suited to the situation where a technique, approach, or body of knowledge is so well-established that courts can safely take judicial notice of its validity on the basis of widely disseminated information and precedent. Sometimes the track record in litigation of various kinds of scientific evidence also suffices to enable courts to take judicial notice that testimony in other suits demonstrates or undermines validity of the process or technique.

Id. (footnotes omitted); see also 1 McCormick, Evidence 203 (Strong ed. 1992) (general acceptance is "a proper condition for taking judicial notice of scientific facts, but it is not a suitable criterion for the admissibility of scientific evidence").

5. See id.

6. We have no "bright line" judicial rule for when a scientific theory or technique becomes so widely accepted or persuasively proven that future courts may take judicial notice of its reliability. However, the more extensive the gatekeeping hearing, the more noted and numerous the experts who testify, submit, affidavits, or otherwise provide information, the more scientific material (both pro and con) that is consulted and discussed at a seminal gatekeeping hearing, the more likely it is that a reviewing court will declare that future trial courts may take judicial notice of the validity or invalidity of that extensively-litigated scientific proposition.

7. For example, either the proponent or opponent of specific scientific evidence might prepare a brief containing excerpts of testimony from other Daubert/Kelly hearings, appropriate affidavits, cites to scientific materials and judicial cases so that when and if the issue next arises, the party is already prepared for recurring Daubert/Kelly challenges.

8. Hernandez, 55 S.W.3d at 705-06; but see id. at 707-08 (Hinojosa, J., dissenting) (citing cases from other jurisdictions which have held urinalysis testing in general and the ADx analyzer in particular scientifically reliable).

9. See Kelly v. State, 824 S.W.2d 568, 573 (Tex. Crim. App. 1992) ("before novel scientific evidence may be admitted under Rule 702, the proponent must persuade the trial court, by clear and convincing evidence, that the evidence is reliable and therefore relevant"); see also Daubert v. Merrell Dow Pharmaceuticals, Inc, 509 U.S. 579, 592 (1993) ("[f]aced with a proffer of expert scientific testimony, then, the trial judge must determine at the outset, pursuant to Rule 104(a), whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue. This entails a preliminary assessment of whether the reasoning or methodology underlying the testimony is scientifically valid and of whether that reasoning or methodology properly can be applied to the facts in issue").

10. The State's legitimate concern at the probation revocation hearing in this case could have been that it was not, at that moment, prepared to conduct a Daubert/Kelly hearing on the reliability of the ADx machine because it had not been given any pre-hearing notice that appellant might contest its scientific reliability. See Judge Harvey Brown, Procedural Issues under Daubert, 36 Hous. L. Rev. 1133, 1142-44 (1999) (discussing advantages and disadvantages of pretrial Daubert hearings and concluding that "courts should normally require parties to make reliability challenges at least thirty days before trial"). In that case, the trial court might well have given the State a continuance to produce testimony, scientific material, or cases to support its position that the ADx machine is a scientifically reliable one.

11. Although a trial judge, like an appellate judge, may not be a trained scientist, the trial judge at least has both parties and their witnesses before him. He may ask questions of the expert witnesses, request more information, ask for additional briefing, or seek clarification concerning the scientific state of the art and reliable sources in the particular field. See E.I. du Pont de Nemours & Co. v. Robinson, 923 S.W.2d 549, 558 (Tex. 1995) (during Rule 104(a) Daubert hearing, trial court need not follow rules of evidence, except those relating to privileges, and should "freely ask questions" of the expert). He is Johnny-on-the-spot. He need not rely solely upon admissible evidence in conducting his "gatekeeping" function (see Tex. R. Evid. 104(a)), but at least the parties have an important role in assisting and guiding him in determining the scientific reliability of the information. See Daubert, 509 U.S. at 579 n.10 (noting that "gatekeeping" hearings are conducted under Rule 104(a) in which the trial court is not bound by the rules of evidence).

Appellate judges, on the contrary, cannot question the witnesses, cannot be assisted by live experts or by the parties' presentation of scientific materials which they believe are reliable and up-to-date, or by factual or scientific distinctions found in cases from other jurisdictions.

12. Of course, had the court of appeals (or another Texas appellate court) already stated that it would take judicial notice of the scientific reliability of the ADx analyzer methodology, then both the trial court or the court of appeals could have relied upon that prior published opinion for support. Here, however, the court of appeals had explicitly found Mr. Perez's ADx testimony inadmissible in an earlier, unpublished opinion. See note 3 supra.

13. Reliance, in Texas criminal proceedings, upon judicial opinions from non-Texas jurisdictions for purposes of judicial notice of the validity of scientific theories or methodologies may be problematic because this Court has decreed that the proponent of expert testimony must prove its reliability by "clear and convincing" evidence. Kelly, 824 S.W.2d at 573. Most other American jurisdictions use the "preponderance of the evidence" standard normally used under Rule 104(a). See, e.g. Daubert, 509 U.S. at 592, n.10; Bourjaily v. United States, 483 U.S. 171, 175 (1987) (party offering evidence for Rule 104(a) determination must show its admissibility under another rule (such as Rule 702) by a preponderance of the evidence); Lauzon v. Senco Prods., 270 F.3d 681, 686 (8th Cir. 2001); Nelson v. Tenn. Gas Pipeline Co., 243 F.3d 244, 251 (6th Cir. 2001). In that respect, this Court stands as an anomaly.