OPINION
ESPINOSA, Chief Judge.¶ 1 A jury found appellant David Douglas Secord guilty of aggravated driving under the influence of an intoxicant (DUI) while his driver’s license was suspended, and the trial court placed him on five years’ probation. On appeal, Secord argues the trial court erred in several evidentiary rulings and in denying his motion to compel the state to reinstate a plea offer. Because we conclude the state may, in appropriate circumstances, properly condition a plea on a defendant’s foregoing disclosure of nonexculpatory evidence, and because Secord’s evidentiary challenges lack merit, we affirm.
Facts and Procedural Background
¶ 2 On September 22, 1998, Deputy Dawn Barkman stopped a vehicle for exceeding the speed limit and driving briefly onto the dirt shoulder of a road. When Barkman approached the driver, Secord, she smelled an intoxicant near the driver’s window. Deputies Woolridge and Hill arrived at the scene and investigated whether Secord had been driving while under the influence of alcohol. During that investigation, Hill conducted three field sobriety tests, including a horizontal gaze nystagmus (HGN) test, a “one-leg stand” test, and a “walk-and-tum” test. Hill observed Secord’s gait, appearance, and speech as he performed the tests. Hill also questioned Secord about his consumption of intoxicants. At the end of the investigation, Hill wrote a report about his observations, noting that he had used a video camera to record his investigation.
*520¶ 3 The state indicted Secord on one count each of aggravated DUI and aggravated driving with an alcohol concentration (AC) level of .10 or more, class four felonies.1 The state later offered to permit Secord to plead guilty to endangerment, a class six felony, and DUI with one prior conviction, a class one misdemeanor. Defense counsel requested that he be provided the police videotape before advising Secord whether he should accept the offer. In response to that request, the state withdrew the plea offer, provided a copy of the videotape to Secord, and transferred the case to a “trial team.”
¶ 4 Secord nevertheless filed with the trial court a request for a change-of-plea hearing, saying he wanted to accept the plea offer and noting the state might oppose the request because he had asked for and had received a copy of the videotape. He argued he was “entitled to review th[e] videotape” under State v. Draper, 162 Ariz. 433, 784 P.2d 259 (1989).2 The state, indeed, opposed Secord’s request to accept the plea offer but offered him a similar agreement that would have required him to serve more time in jail. Following a hearing, the trial court rejected Secord’s argument that he had possessed a due process right to review the videotape before deciding whether to accept the original plea offer.3 Secord declined the second plea offer, and a jury later found him guilty.
Conditional Plea Offer
¶ 5 Secord argues the trial court erred in denying his motion to compel the state to reinstate its original plea offer, asserting that the prosecutor violated Secord’s right to due process by conditioning the offer on his foregoing disclosure of the videotape of his DUI investigation. The state responds that its broad discretion in charging defendants and negotiating plea agreements entitled it to withdraw the plea offer. In general, we defer to a trial court’s findings of fact but review de novo its conclusions of law. State v. Lucas, 199 Ariz. 366, 18 P.3d 160 (App.2001).
¶ 6 “It is well settled that criminal defendants have no constitutional right to a plea agreement and the state is not required to offer one.” State v. McKinney, 185 Ariz. 567, 575, 917 P.2d 1214, 1222 (1996). Moreover, the state may refuse to plea bargain so long as it has “some valid reason” and no invidious discrimination is involved. State v. Martin, 139 Ariz. 466, 481, 679 P.2d 489, 504 (1984). When the state does offer a plea agreement, it is free to include such conditions and terms as it deems appropriate, even harsh or coercive ones, so long as the defendant is free to accept or reject the offer. State v. Morse, 127 Ariz. 25, 617 P.2d 1141 (1980); State v. McInelly, 146 Ariz. 161, 704 P.2d 291 (App.1985); see also State v. Felix, 153 Ariz. 417, 737 P.2d 393 (App.1986).
¶ 7 In Draper, our supreme court held that a condition in a plea offer that prevented the defendant from interviewing a victim' — and thereby discovering obviously relevant evidence — did not necessarily violate due process or run counter to public policy.4 Instead, the court looked to whether the defendant’s acceptance of the plea offer could *521nevertheless be considered to have been voluntary and intelligent and remanded the case for a determination of that issue. More recently, in United States v. Ruiz, 536 U.S. 622, 122 S.Ct. 2450, 153 L.Ed.2d 586 (2002), the United States Supreme Court addressed a similar situation. There, the prosecution’s proposed plea agreement offered the defendant a recommendation for a reduced sentence in exchange for her waiving her right to receive material impeachment evidence about informants and other witnesses as well as evidence supporting any affirmative defense she might assert at trial. The Court held that the plea offer did not violate the Constitution, stating that “the need for this information is more closely related to the fairness of a trial than to the voluntariness of the plea.” Id. at 633, 122 S.Ct. at 2457, 153 L.Ed.2d at 597.
¶8 Secord contends that the videotape was “critical evidence” necessary to his decision whether to accept the plea offer, a theory embraced by our dissenting colleague. It is clear, however, that the Constitution does not require that a defendant have “complete knowledge” of the state’s potential case against him or her and permits a trial court to accept a guilty plea despite “various forms of misapprehension under which a defendant might labor.”5 Id. at 630, 122 S.Ct. at 2456, 153 L.Ed.2d at 596; see Brady v. United States, 397 U.S. 742, 90 S.Ct. 1463, 25 L.Ed.2d 747 (1970) (intelligent and voluntary guilty plea does not require that defendant have no misapprehension about strength and quality of prosecution’s case); see also Weatherford v. Bursey, 429 U.S. 545, 559, 97 S.Ct. 837, 846, 51 L.Ed.2d 30, 42 (1977) (“There is no general constitutional right to discovery in a criminal case.”).
¶ 9 It is equally clear that Secord had adequate information on which to “assess the strength of the state’s case,” Draper, 162 Ariz. at 437, 784 P.2d at 263, and to ground a sufficiently knowing and voluntary decision to either accept or reject the state’s plea offer. He had been charged with one count each of aggravated DUI in violation of A.R.S. § 28-1381(A)(1) and aggravated driving with an AC of .10 or more in violation of former A.R.S. § 28-1381(A)(2). See 1997 Ariz. Sess. Laws, ch. 1, § 106. The first charge required the state to prove that Secord’s control of his vehicle had been impaired or “to the slightest degree affected by his consumption of the intoxicant.” Davis v. Waters, 103 Ariz. 87, 90, 436 P.2d 906, 909 (1968); see also State ex rel. McDougall v. Albrecht, 168 Ariz. 128, 811 P.2d 791 (App.1991); State v. Superior Court, 150 Ariz. 18, 721 P.2d 676 (App.1986). The second required proof that Secord’s AC had been .10 or greater “within two hours of driving or being in actual physical control of the vehicle.” 1997 Ariz. Sess. Laws, ch. 1, § 106.
¶ 10 In Draper, the court noted that “[o]ther witnesses, evidence and the record available to a defendant at the time of entering the plea agreement,” might be adequate for purposes of an intelligently entered plea. 162 Ariz. at 437, 784 P.2d at 263. At the time the state made its initial plea offer, it had provided Secord the written reports of Barkman, Woolridge, and Hill, which described Secord’s driving, demeanor, appearance, symptoms of intoxication, and poor performance on the field sobriety tests. Secord also had the results of a preliminary breath test showing his AC had been well above the then-legal limit of .10 and a laboratory report of a blood test showing an AC of .105.6 Moreover, he had exhibited six out of six signs on the HGN test, evidence that was admissible to corroborate his breath test results. See Hamilton v. Mesa City Court, 165 Ariz. 514, 799 P.2d 855 (1990); State v. Herrera, 203 Ariz. 131, 51 P.3d 353 (App.2002). We thus disagree with the dissent’s characterization of this ease as a “close” one and the videotape as “pivotal.” We conclude that, although the videotape of Hill’s portion *522of the investigation was clearly relevant and potentially useful to Seeord’s defense, it was not indispensable to his intelligent and knowing evaluation of whether to accept the state’s plea offer. See Ruiz; Felix; State v. Caperon, 151 Ariz. 426, 728 P.2d 296 (App. 1986). Accordingly, we find no error in the trial court’s denial of Secord’s motion to compel the state to reinstate its first plea offer.7
Evidentiary Rulings
¶ 11 Secord also asserts the trial court committed numerous reversible errors in its evidentiary rulings. We will not disturb a trial court’s decision to admit or exclude evidence absent an abuse of discretion. State v. Davis, 205 Ariz. 174, 68 P.3d 127 (App.2002).
a. Evidence of Vieodin use
¶ 12 Secord first argues the trial court erred in admitting other act evidence that he had taken Vieodin, a prescription medication, earlier in the day he was arrested. In discussing Secord’s motion in limine to preclude mention of his use of Vieodin, the prosecutor stated that the criminalist, Terri Gallegos, would testify about the effects of Vieodin when combined with alcohol. The court reserved its ruling on Secord’s motion. At trial, although Gallegos said she knew about the chemical compounds and their effects on the body, she could not explain how the medication Secord had taken, combined with the alcohol he had consumed, would have affected his ability to judge, perceive, and react. The court then sustained Se-cord’s objection and prohibited any further testimony about Vieodin.
¶ 13 Although the jury had heard Gallegos testify that Vieodin is a “narcotic analgesic” and that it acts as a “central nervous system depressant,” there was no further testimony about it, and the prosecutor did not refer to it in argument. The court instructed the jury not “to be concerned about the Vieodin,” saying it was “not to consider any Vieodin or any medication, prescription or otherwise, that may have been in Mr. Secord’s system because there is no evidence to indicate that [it] had any effect on him.” Secord did not object to these instructions, and we presume the jurors followed them. See State v. Prince, 204 Ariz. 156, 61 P.3d 450 (2003); State v. LeBlanc, 186 Ariz. 437, 924 P.2d 441 (1996). Accordingly, we see no reasonable possibility that Secord was prejudiced by the limited testimony about his Vieodin use and no reason to reverse his convictions on this ground.
b. Prosecutorial misconduct
¶ 14 Alternatively, Secord contends the prosecutor committed misconduct by misrepresenting the criminalist’s ability to connect Secord’s Vieodin usage to the DUI charge. To warrant a reversal based on prosecutorial misconduct, the conduct “must have so permeated the trial that it probably affected the outcome and denied defendant his due process right to a fair trial.” State v. Blackman, 201 Ariz. 527, ¶ 59, 38 P.3d 1192, 1206 (App.2002). Even if misconduct occurs, it “is harmless if we can conclude beyond a reasonable doubt that it did not contribute to or affect the verdict.” State v. Towery, 186 Ariz. 168, 185, 920 P.2d 290, 307 (1996). The trial court commented that the prosecutor had had a good faith basis for attempting to introduce evidence of Secord’s Vieodin use,8 but was simply unable to provide enough foundation for its admission. We cannot say the court abused its discretion in finding that no misconduct had occurred. See State v. Bolton, 182 Ariz. 290, 307, 896 P.2d 830, 847 *523(1995) (“Motions for mistrial based on prose-cutorial misconduct are committed to the trial court’s discretion, which will not be disturbed on appeal unless plainly abused.”); State v. Korovkin, 202 Ariz. 493, ¶ 8, 47 P.3d 1131, 1133 (App.2002) (appellate court defers to trial court’s findings of fact related to prosecutorial misconduct).
c. Preliminary breath test
¶ 15 Secord also assigns error to the trial court’s admission of the results of a preliminary breath test Woolridge administered at the scene of the stop. During Wool-ridge’s cross-examination, defense counsel asked him why he had not performed a drug recognition evaluation. Out of the presence of the jury, Woolridge explained that the results of Secord’s preliminary breath test showed his AC was .113, which was consistent with the symptoms he had exhibited. Finding the defense had “opened the door,” the court permitted Woolridge to answer that the initial test had showed the presence of alcohol, but did not allow him to give the numeric result. Contrary to Secord’s assertion, nothing in Woolridge’s statement implied that Secord had had a higher AC than the .09 to which Gallegos had testified.
d. Limitation of impeachment evidence
¶ 16 Secord next argues that the trial court erred in preventing him from impeaching his AC test results with evidence that the criminalist who had first tested his blood sample, Roger Corcoran, had been fired for “misconduct on the job,” including accessing pornographic websites, tampering with evidence, and releasing confidential information. Gallegos later retested Secord’s sample. After reviewing Corcoran’s personnel file, the trial court disallowed the evidence as hearsay and irrelevant because Corcoran was not testifying and the results of his testing were not being proffered. Clearly, the reasons for Corcoran’s termination were not probative of whether Gallegos’s test results were accurate or whether Secord had been driving while under the influence of alcohol. See Ariz. R. Evid. 401, 17A A.R.S. (evidence is relevant when it has “any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence”); Ariz. R. Evid. 402 (evidence must be relevant to be admissible). The trial court properly excluded the evidence about Corcoran.
e. Chain of custody
¶ 17 Secord also challenges the chain of custody of the vial of blood Gallegos had tested, asserting her testimony “did not ‘strongly suggest’ that there was no possibility of substitution or tampering.” To establish the requisite chain of custody of an evidentiary item, the state must show that possession was continuous and that the evidence is intact and unaltered. State v. Jackson, 170 Ariz. 89, 821 P.2d 1374 (App. 1991). If the state makes this showing, a trial court should admit the evidence “unless the defendant offers proof that the evidence has changed or been tampered with.” Id. at 93, 821 P.2d at 1378.
¶ 18 Gallegos testified that the property control sheet showed the signature and date for each person who had handled the vials of Secord’s blood and his or her purpose in doing so. Gallegos said Secord’s blood had been tested twice by another analyst before she performed her test. The seals were intact on the box in which the sample was stored, and Gallegos did not detect anything indicating anyone had tampered with it. Secord takes issue with Gallegos’s testimony that the identifying labels on the vials had been removed. But, as the court correctly ruled, flaws in the chain of custody go to the weight of the evidence, not its admissibility. State v. Morales, 170 Ariz. 360, 824 P.2d 756 (App.1991). Here, the state showed that the vials in question were always in police possession. In the absence of any evidence to the contrary, this was sufficient to show the chain of custody. See Jackson; State v. Moreno, 26 Ariz.App. 178, 547 P.2d 30 (1976).
f. Cumulative error
¶ 19 Lastly, Secord maintains that all the asserted errors combined “led the jury to the inevitable conclusion that inadmissible blood tests showed a higher alcohol content than that disclosed to the jury and thereby preju*524diced [him], violating due process.” But we have found no merit to any of his asserted errors, and Arizona does not subscribe to the cumulative error doctrine in this context. State v. Hughes, 193 Ariz. 72, 969 P.2d 1184 (1998); State v. Prince, 160 Ariz. 268, 772 P.2d 1121 (1989); State v. Curry, 187 Ariz. 623, 931 P.2d 1133 (App.1996).
¶ 20 For all of the foregoing reasons, we affirm Secord’s convictions and placement on probation.
PELANDER, P.J., concurs.. The latter charge was ultimately dismissed at trial because a retest of Secord's blood sample resulted in an AC of .09.
. In Draper, the supreme court addressed whether the state had violated the defendant's right to due process by conditioning a plea offer on the defendant’s waiver of his right to certain disclosure. In anchoring his claim on Draper, Secord sufficiently presented his due process claim to the trial court and, therefore, contrary to the state's argument, did not waive it on appeal.
. We note that Secord did not seek special action relief from this interlocutory decision, instead choosing to proceed to trial. Although it would have been preferable for Secord to raise the issue by special action, we do not address whether his failure to do so waived the issue on appeal, neither side having briefed the matter. See State v. Espinosa, 200 Ariz. 503, 29 P.3d 278 (App. 2001) (had defendant timely challenged withdrawal of plea offer, either party could have sought special action relief from court's ruling); State v. Superior Court, 183 Ariz. 327, 903 P.2d 635 (App.1995) (special action jurisdiction accepted because no adequate remedy by appeal of trial court's rejection of plea agreement); State ex rel. Bowers v. Superior Court, 173 Ariz. 34, 839 P.2d 454 (App.1992) (special action appropriate vehicle for state's challenge to trial court’s interlocutory order rejecting plea agreement).
. Draper preceded the victims rights provisions in the Arizona Constitution, Art. II, Sec. 2.1, and A.R.S. § 13-4401 et. seq.
. It should be emphasized we are not faced with the issue of whether the state may condition a defendant's acceptance of a plea offer on the state’s nondisclosure of evidence in its possession it knows to be exculpatory or that establishes the defendant’s factual innocence. See McCann v. Mangialardi, 337 F.3d 782 (7th Cir.2003).
. At trial, a police criminalist testified that a subsequent retest in July 2001 had resulted in an AC of .09 and that the variance was due to the length of time the sample had been in storage and the repeated opening of the vials for testing.
. The dissent takes us to task for not engaging in a "weigh[ing of] the state’s interest in withholding the videotape against the defendant’s need of it,” citing Draper. Infra, ¶ 25. But it is difficult to understand how the state’s interest in not disclosing a particular piece of nonexculpatory evidence (for example, a crime victim’s statement or the identity of a confidential informant) has much, if any, bearing on a defendant’s evaluation of a plea offer if clear and sufficient evidence of the defendant’s culpability is within his or her possession at the time of the offer. Moreover, Draper suggested such a balancing test in remanding that case for a determination of whether the withheld evidence "somehow prevented [the defendant] from entering an intelligent plea,” 162 Ariz. at 438, 784 P.2d at 264, a situation not present here.
. We note that no actual evidence that Secord had taken Vieodin on the day of his arrest was ever admitted.