Defendant was convicted by a jury of operating a motor vehicle while under the influence of intoxicating liquor causing serious injury, MCL 257.625(5); MSA 9.2325(5). He was sentenced to five years’ probation with the first forty-five days to be served in the county jail. Defendant appeals his conviction as of right. We reverse.
On appeal, defendant claims that the trial court erred in admitting blood alcohol test results into evidence. We agree.
The decision whether to admit evidence is within the sound discretion of the trial court and will not be disturbed on appeal absent an abuse of discretion. People v Lugo, 214 Mich App 699, 709; 542 NW2d 921 (1995); Price v Long Realty, Inc, 199 Mich App 461, 466; 502 NW2d 337 (1993). An abuse of discretion is found only if an unprejudiced person, considering the facts on which the trial court acted, would say there was no justification or excuse for the ruling made. People v McAlister, 203 Mich App 495, 505; 513 NW2d 431 (1994).
Defendant was charged and convicted under MCL 257.625(5); MSA 9.2325(5), which makes it a felony to operate a motor vehicle while under the influence of intoxicating liquor and cause serious impairment of a body function to another person. Defendant claims that the trial court abused its discretion in admitting the chemical test results because the delay between the time of the crime and the administration of the test rendered the test results unreliable. The parties *4agree that the delay in this case was between two hours and eight minutes and two hours and twenty minutes. The issue, then, is whether the test results remain sufficiently reliable and accurate after such a delay to allow the presentation of that evidence to the jury to be considered in deciding whether defendant was intoxicated at the time he operated a motor vehicle and caused serious injury to another person.
In order for chemical test results to be admitted into evidence, the prosecutor must meet four foundational requirements: (1) the operator administering the test was qualified, (2) the proper method or procedure was followed in administering the test, (3) the test was performed within a reasonable time after the arrest, and (4) the testing device was reliable. People v Jacobsen, 205 Mich App 302, 305; 517 NW2d 323 (1994), rev’d 448 Mich 639; 532 NW2d 838 (1995)1; People v Kozar, 54 Mich App 503, 509, n 2; 221 NW2d 170 (1974). The only foundational requirement at issue in this case is whether the blood alcohol test was administered within a reasonable amount of time. Whether the delay was reasonable is a determination left to the discretion of the trial court. Jacobsen, supra, 205 Mich App 306; MRE 104(a).
According to this Court in Kozar, supra at 508, a defendant’s blood alcohol content at the time of the offense should be considered the equivalent of the blood alcohol content at the time of the test, provided the four prerequisites to the admission of the evi*5dence are met. See also Jacobsen, supra, 205 Mich App 305. If the test was performed within a reasonable amount of time, the prosecution need not relate back through expert testimony the results of the test to the time of the offense as a condition precedent to the admission of the evidence. Kozar, supra at 507. This Court in Jacobsen, supra, 205 Mich App 306-307, explained that the requirement that the blood alcohol test be performed within a reasonable amount of time after the arrest is to ensure that the test results accurately reflect the defendant’s blood alcohol content at the time he was arrested. In People v Krulikowski, 60 Mich App 28, 33; 230 NW2d 290 (1975), this Court stated that a failure to adduce evidence of the foundational requirements “precludes the admission of the test results into evidence, and does not go merely to the weight which the trier of fact may accord the test results” (emphasis in original). This requirement, however, is not meant to “place the trial bench in a judicial straitjacket with respect to the laying of a foundation as a condition precedent to the admission of evidence.” Id. Rather, the trial bench still possesses considerable discretion regarding the adequacy of the foundation in any given case, and its determination should not be lightly set aside. Id.
The parties rely on People v Schwab, 173 Mich App 101, 103; 433 NW2d 824 (1988), where this Court reiterated the four prerequisites to the admission of chemical blood test results. As in this case, the only error claimed by the defendant in Schwab related to the reasonable time prerequisite. Id. Defendant relies on Schwab because there, the Court upheld the district court’s ruling that a two- hour and thirteen-minute delay in administering the chemical test was *6unreasonable and precluded admission of the test results. Id. at 105. Defendant contends that the two-hour and eight-minute or the two-hour and twenty-minute delay in this case is likewise unreasonable.2
In Schwab, the defendant was arrested and Breathalyzer tests were administered approximately two hours and fifteen minutes after he was first stopped by the police. Id. at 102. The defendant moved to suppress the results of the tests and the district court granted his motion. The people sought leave to appeal in the circuit court. The circuit court granted leave and ordered the district court to conduct an evidentiary hearing to determine the effect of the passage of time on the reliability of the Breathalyzer tests. The district court then heard extensive expert testimony regarding the rate at which alcohol is metabolized, how likely it is to be absorbed into the stomach, and the many variables that can have an effect on the rate of absorption and metabolism. Id. at 103-104. The district court further heard extensive testimony relating to the reasonableness of the delay in administering the Breathalyzer tests and concluded that the tests were not sufficiently probative of the defendant’s blood alcohol level at the time of his arrest. The circuit court affirmed. This Court also affirmed, finding that the district court did not abuse its discretion in suppressing the results of the Breathalyzer tests, but declining the parties’ invitations to establish a bright-line rule that would include or exclude the results of a Breathalyzer test depending on the time delay *7before the test is given. Instead, this Court stated that reasonableness varies from one factual setting to the next and must therefore be considered case by case. Id. at 105.
Under Kozar, supra, Schwab, supra, and Jacobsen, supra, the prosecution must establish that there has not been unreasonable delay in the time between the arrest and the administration of the test. In these three cases, this Court appears to refer to the time of arrest and the time of the offense interchangeably. Presumably, this Court does not distinguish the two events because both occur close in time under the facts of each case. Notably, the offense of operating a motor vehicle while under the influence of intoxicating liquor makes it illegal to be intoxicated at the time of driving, MCL 257.625(5); MSA 9.2325(5), not at the time of arrest. Therefore, the proper focus of the reasonable time delay inquiry begins with the time of the offense.
In the present case, the trial court agreed that the appropriate inquiry relates to the time of defendant’s operation of the motor vehicle and the time the test was administered. Given this time frame, the trial court ruled that the delay in this case was reasonable. In making its decision, the trial court considered the deposition testimony of defendant’s expert, Dr. Dennis Simpson, an expert in the area of physiology of alcohol absorption and elimination, regarding how alcohol is absorbed and eliminated by the body over time. Dr. Simpson testified that the blood alcohol test taken at 12:50 A.M. on September 17 had no scientifically probative value with regard to defendant’s blood alcohol content during the period between 10:30 p.m. and 10:42 P.M. the night before. He stated that there *8was no way to determine whether defendant’s blood alcohol content was above 0.09 percent between 10:30 P.M. and 10:42 p.m. given the data available in this case. Also, Dr. Simpson could not determine whether defendant’s blood alcohol level was rising or falling during the over two-hour delay. According to Dr. Simpson, the range in which a person’s blood alcohol content increases after consuming the last drink is somewhere between fifteen minutes and four hours and two minutes.3 In order for him to determine *9where a person falls within this range, he would need to know much more than the individual’s height, age, weight, and gender. He would need to know the results of liver function and gastrointestinal tests, what the person ate during that time, what other drugs the person was consuming, the effects of an accident or trauma on the individual, the specific alcohol that was consumed, the rate at which it was consumed, and several other variables. Additionally, Dr. Simpson stated that the preliminary breath test administered to defendant at 12:27 A.M. on September 17 with a result of 0.09 percent was not probative of the blood alcohol level because it is a different measurement from the blood test and does not have the reliability that a blood test in a medical setting would have. The only conclusion Dr. Simpson could draw from the preliminary breath test and the blood test was that defendant had been consuming alcohol that night and at 12:50 A.M. on September 17, defendant had a blood alcohol level of 0.09 percent.
Notwithstanding the undisputed expert testimony, the court ruled that the blood alcohol test results were admissible because the delay was reasonable. The court stated that jurors could weigh the testimony of Dr. Simpson regarding whether the test results were probative of defendant’s blood alcohol level at the time of the improper driving.
The prosecution claims that the trial court correctly determined that the suppression argument was one of weight by finding that the chemical test results were probative and valuable to the jury in its review of evidentiary proofs. However, this position is contrary to the holding in Krulikowski, supra at 33, in which this Court expressly stated that failure to establish the *10requisite foundation for admission of the chemical test results precludes the admission of the test results into evidence, and is not relevant merely to the weight that a trier of fact may assign the test results.
The prosecution in this case failed to offer any evidence that the test results accurately reflected defendant’s blood alcohol level at the time of the offense. The only expert testimony offered in the matter was that of defendant’s expert, Dr. Simpson, whose uncontroverted testimony provided that the two-hour and eight-minute or the two- hour and twenty-minute delay rendered the test results unreliable as an indicator of defendant’s blood alcohol level at the time of the offense. Even given the trial court’s rejection of the expert’s testimony that the delay was unreasonable, there is no evidence in the record on which the court could base its decision that the test results were reliable and the delay was therefore reasonable. Because the prosecution did not offer any evidence of reliability given the delay, the prosecution failed to carry its burden of proof. See Krulikowski, supra at 33. An abuse of discretion is found only if an unprejudiced person, considering the facts on which the trial court acted, would say there was no justification or excuse for the ruling made. McAlister, supra at 505. Here, the trial court abused its discretion because there is no justification in the record for the trial court’s determination that the delay was reasonable.
We have considered the issue whether the error was harmless but cannot say that it is highly probable that the error did not affect the outcome at trial. See People v Harris, 458 Mich 310, 320; 583 NW2d 680 *11(1998); People v Mitchell (On Remand), 231 Mich App 335; 586 NW2d 119 (1998).
Reversed.
Sawyer, P.J., concurred.The Supreme Court reversed this Court’s decision in Jacobsen that the trial comí should have appointed an expert. The Supreme Court ruled that the defendant did not make the requisite threshold showing of need for the expert. However, the Supreme Court’s ruling does not disturb this Court’s discussion of the foundational requirements and the reasonableness inquiry relating to the admissibility of chemical test results.
We do not decide that the mean delay here is one minute afoul of the Schwab perimeter.
During his deposition, Dr. Simpson answered questions relating to the following stipulated fact pattern: Defendant was involved in a motor vehicle accident on September 16, 1995, between 10:30 p.m. and 10:42 p.m.; an officer administered a preliminary breath test at approximately 12:27 am. the following morning, with a result of 0.09 percent; defendant’s blood was drawn at approximately 12:50 am. for a blood alcohol test; and the blood alcohol test result indicated 0.09 percent blood alcohol. Given these facts, Dr. Simpson concluded that the blood alcohol test level of 0.09 at 12:50 am. was not, within a reasonable degree of scientific certainty, probative of defendant’s blood alcohol level during the time between 10:30 p.m. and 10:42 p.m. on September 16, 1995. According to Dr. Simpson, under the facts of this case, the only conclusion that could be drawn from a blood alcohol level of 0.09 at 12:50 a.m. is that the blood alcohol level was 0.09 at 12:50 am. Dr. Simpson’s testimony at trial was substantively the same as that given during his deposition. The trial court stated its problem with the testimony of defendant’s expert witness as follows:
The difficulty I have with — with the premise being posed here today, is this: If ... I were to take the testimony of Dr. Simpson, accept it. . . completely then it is virtually impossible to ever get any information. He says it’s impossible to relate it back. Well, the . . . Rules of Evidence are predicated on probative value. He may feel, Dr. Simpson may feel that it’s scientifically impossible. But, we do not deal with scientific probabilities on the admissibility of evidence, nor on the burden of proof in a criminal case, which is beyond a reasonable doubt. And, that word, [r]easonable i[s] the burden that a jury has to use in establishing the elements of the offense, is built into the law of evidence also.
Thereafter, the trial court ruled that the blood alcohol test results were admissible, stating that the jurors could weigh the testimony of Dr. Simpson regarding whether the test results were probative of defendant’s blood alcohol level at the time of the crime.