(concurring). I agree with the majority that the test results should not be sup*458pressed in this case. However, I write because I would impose an affirmative duty on the state,- in the future, to preserve blood samples that are material to the defendant’s innocence or guilt. I believe that such a duty is consistent with due process requirements, and is necessary for the sound administration of the criminal justice system.
This court has recognized that evidence destroyed by the prosecution could deny a defendant due process, “. . . given the showing that the evidence was clearly material to the issue of guilt or innocence.” State v. Amundson, 69 Wis. 2d 554, 578, 230 N.W.2d 775 (1975). In State v. Walstad, 119 Wis. 2d 483, 351 N.W.2d 469 (1984), decided today, the majority opinion, which I joined, held that the destruction of a breathalyzer test ampoule did not deny the defendant due process. Slip op. at 486, infra. The record below clearly showed that the used test ampoule could not be retested so as to provide material evidence. The majority noted that the test ampoule “. . . was not material evidence of the defendant’s guilt or innocence, because the ampoule, had it been preserved, could not have been retested or reexamined in a manner that would provide relevant evidence either in respect to the accuracy of the original test or to the guilt or innocence of the defendant.” Slip op. at 486, infra.
A far different situation is presented, however, when the state or its agents has taken a blood sample from a defendant for testing purposes, and all or part of the sample remains after the tests have been completed, and then all or part of the sample is destroyed, thereby precluding the defendant from conducting any type of scientific tests on the sample. Scientific literature indicates that a blood sample, unlike a breath ampoule, remains testable for many purposes for several months after it is taken if the sample has been properly stored. See, e.g., Stewart and Stolman, Toxicology Mechanisms and Analytical Meth*459ods, Vol. II at 116-17 (1961) ; Alcohol and the Impaired Driver, American Medical Association, at 68-72 (1968). Thus, unlike a breathalyzer test ampoule, if all or part of a blood sample remains after it is tested by the state, and that remaining portion is properly stored, it is possible that the remainder could be tested for blood alcohol content months after the sample was taken, and could yield results that are material to the defendant’s innocence or guilt with respect to a charge relating to intoxication.
Additionally, it is possible that a properly stored blood sample, unlike a breathalyzer test ampoule, could be tested several months after it was taken for purposes in addition to determining blood alcohol content, such as determining blood type and the presence or absence of foreign matter. In a given case, a determination of blood type could be material to a defendant’s guilt or innocence. For example, suppose a defendant has reason to believe that the sample upon which the state is relying is not his or her blood, and that the chain of custody is faulty. If the state or its agents has destroyed the blood sample, and the defendant is therefore unable to conduct a test on the sample to determine blood type, the defendant might be foreclosed from conclusively proving his or her innocence.
In addition, suppose a defendant is arrested for homicide or injury by intoxicated use of a vehicle, and the state or its agents destroys that part of the defendant’s blood sample remaining after the state has tested for blood alcohol content. Suppose further that the defendant’s defense is that the cause of the faulty driving was not the level of intoxication at the time of arrest, but was due to some other factor which could be established by showing the presence of foreign matter in the blood. Presumably, the presence or absence of foreign matter in the blood sample would be material to the defendant’s guilt or innocence, yet the defendant would be precluded by the state’s destruction of the sample from conducting a test *460to show the presence or absence of such foreign matter. This in turn could prevent the defendant from conclusively establishing his or her innocence. The destruction of the blood sample under circumstances described in these examples might well deny a defendant due process.
I would therefore hold that: 1) if the state has taken a blood sample and in good faith subjected it to scientific tests; and 2) if an amount sufficient for further testing remains but is then non-maliciously destroyed before the defendant can test it; and 3) if the defendant establishes the materiality of the blood sample, then the test results are inadmissible in evidence unless the state can show that it had established, enforced, and attempted in good faith to adhere to rigorous and systematic procedures designed to preserve the evidence. This holding would not apply if the state, in good faith, had subjected the sample to scientific testing and the sample was destroyed because of the nature of the testing process. Given the minimal burden that would be imposed on the state by requiring preservation of blood samples as long as they remain material, I believe such a holding is necessary both to fully safeguard the due process rights of defendants, and to promote the sound administration of the criminal justice system.
I would apply the above holding prospectively only. In this case and in all prior cases dealing with the non-malicious destruction of blood samples by the state, I would hold that in order for the results of a blood test to be admitted into evidence, if the defendant establishes materiality, the state must show beyond a reasonable doubt that the non-malicious destruction of the evidence was accidental or was pursuant to routine practice or procedure established by the state or its agents.
In this case, it is undisputed that the blood sample was destroyed pursuant to routine practice. In addition, there *461is no evidence that the sample was destroyed in bad faith. Therefore, I agree with the majority that the test results should not be suppressed.
I am authorized to state that Justice William G. Callow joins in this concurring opinion.