Brian Paul Stephens, petitioner, Appellant, vs. Commissioner of Public Safety, Respondent.

may not be cited except as provided by

Minn. Stat § 480 A. 08, subd. 3 (1996)

 STATE OF MINNESOTA

 IN COURT OF APPEALS

  C9-98-503

Brian Paul Stephens, petitioner,

Appellant,

vs.

Commissioner of Public Safety,

Respondent.

  Filed September 1, 1998

 Affirmed

  Lansing, Judge

Washington County District Court

File No. C8974513

Douglas V. Hazelton, 10 South Fifth Street, Suite 480, Minneapolis, MN 55402-1004 (for appellant)

Hubert H. Humphrey III, Attorney General, Jeffrey S. Bilcik, Assistant Attorney General, 525 Park Street, Suite 200, St. Paul, MN 55103 (for respondent)

Considered and decided by Lansing, Presiding Judge, Harten, Judge, and Forsberg, Judge.*

  U N P U B L I S H E D O P I N I O N

 LANSING, Judge

We review an order sustaining the revocation of a driver's license under the implied consent law. The record supports the district court's determination on the validity and reliability of the Intoxilyzer test, and we affirm.

  FACTS

The revocation of Brian Stephens' driver's license was based on an Intoxilyzer test administered by the Washington County Sheriff's Office. Deputy Michael Lindholm testified that he monitored Stephens during the 15-20 minute pretest period and observed no activities that he believed would affect the validity of the test.

At the conclusion of the pretest monitoring, Lois Arends, a certified Intoxilyzer operator, ran the Intoxilyzer test. Arends testified that the test record indicated that the machine was functioning normally; the printout stated "diagnosis OK," all four air blank tests showed a concentration of .000, and the calibration test reported a value of .108, within the range of acceptable values.

Stephens' breath samples had a reported value of .134 with a replicate reading of .136 and, the second breath sample five minutes later, a value of .141 with a replicate reading of .145. The final reported value was .13 with a 95-percent correlation. Arends observed nothing about the test or Stephens' conduct during the test that she believed would invalidate the breath results.

Stephens testified that the Intoxilyzer test did not accurately report his alcohol concentration level because he had consumed only two beers in the eight hours preceding the test. He attributed the test results to his gastroesophageal reflux condition. He did not explain the condition to Lindholm or Arends, but did tell Lindholm that approximately 14 hours earlier, he had taken Pepcid, a prescription drug that reduces stomach acidity. Stephens also produced expert testimony that the test was invalid because mouth alcohol caused by gastroesophageal reflux could evade the Intoxilyzer mouth alcohol detection system and distort the result.

The district court found that the reflux condition did not influence the Intoxilyzer test and that the test was valid, reliable, and accurate. Based on this finding, the court sustained the revocation of Stephens license, and Stephens appeals.

  D E C I S I O N

The proponent of a chemical or scientific test must establish that the test is reliable and that its administration in the particular instance conformed to the procedure necessary to ensure reliability. State v. Dille, 258 N.W.2d 565, 567 (Minn. 1977). The results of an Intoxilyzer, an infrared breath-testing device, are admissible as a trustworthy and reliable measure of breath alcohol if the test is performed by a properly certified operator. Minn. Stat. § 634.16 (1996); Bond v. Commissioner of Pub. Safety, 570 N.W.2d 804 (Minn. App. 1997). When the prima facie requirements are met, it is incumbent on the opponent of the test to demonstrate why it is untrustworthy. Id. Although the ultimate burden of proof remains with the proponent, the test's opponent must provide more than speculation or conjecture to demonstrate invalidity. Hager v. Commissioner of Pub. Safety, 382 N.W.2d 907, 909 (Minn. App. 1986).

The commissioner established that the test was administered by a certified Intoxilyzer operator, that the air blank and calibration standard test results were within acceptable working order, and that the operator had no reason to believe that the test results were invalid. Stephens does not directly dispute the admissibility of the test results, but contends that the district court erred in finding the results reliable in light of his defense that his gastroesophageal reflux condition produced mouth alcohol that invalidated the test.

Stephens' defense is based on his testimony that because he had consumed only two beers the test results must have been artificially elevated by mouth alcohol and that the mouth alcohol was not detected by the Intoxilyzer because the slope detector device that rejects an invalid mouth-alcohol sample is improperly designed. The argument that two beers could not produce a valid .13 reading is self-referential and must be resolved on credibility rather than scientific evidence. In evaluating credibility, the district court was required to weigh Stephens' statement that he had only two beers against Lindholm's testimony that Stephens had difficulty balancing in the field sobriety tests and Stephens' appearance indicated that he had consumed much more than two beers. The district court could also take into account Stephens' testimony at the hearing that demonstrated inconsistency with his arrest statements on whether he had consumed one beer or two beers and whether he had taken the Pepcid in the morning or afternoon.

Stephens' expert testimony is similarly premised on the credibility of Stephens' statements on his alcohol consumption, his pattern of blowing into the Intoxilyzer, and the gastric content in his esophagus. Stephens' expert acknowledged that his opinion on the test's invalidity necessarily accepted Stephens' statements about alcohol consumption and his statement of how he had blown into the machine. His expert also acknowledged that the two consistent Intoxilyzer readings separated by five minutes weighed against a false-elevation-by-mouth-alcohol explanation. Stephens' expert, relying on unproduced articles, also testified that the mouth alcohol detector could malfunction because of its construction. But even if accepted, the testimony showed only that the device could malfunction, not that it did.

On this record, we find no error in the district court's factual findings that sustained its legal conclusion. See State v. George, 557 N.W.2d 575, 578 (Minn. 1997) (on appeal, factual determinations of district court will not be reversed unless clearly erroneous).

Affirmed.

*Retired judge of the Minnesota Court of Appeals, serving by appointment pursuant to Minn. Const. Art. VI, § 10.