Opinion of the Court
GIERKE, Judge:1. Appellant tested positive in a random urinalysis and was charged with wrongfully using cocaine, in violation of Article 112a, *301Uniform Code of Military Justice, 10 USC § 912a. On December 9, 1991, the military judge granted a defense motion to retest appellant’s urine sample for the presence of ecgoninemethylester (EME), raw cocaine, and benzoylecgonine (BE). The convening authority refused to order the retest, and the military judge abated the proceedings.
2. The Government appealed the military judge’s abatement order under Article 62, UCMJ, 10 USC § 862 (1983). On April 28, 1992, the Court of Military Review1 held that the military judge abused his discretion by ordering the retest and abating the proceedings. 34 MJ 1056, 1061. On April 29, 1992, appellant petitioned this Court to review the decision of the Court of Military Review. 36 MJ 23. On June 2, 1992, we denied appellant’s petition without prejudice to appellant’s right to raise the issue during the ordinary course of appellate review. 36 MJ 47.
3. On June 12, 1992, appellant’s general court-martial continued; and, contrary to his pleas, the military judge, sitting as a general court-martial, convicted him as charged. The approved sentence provides for a bad-conduct discharge, confinement for 30 days, forfeiture of $500.00 pay, and reduction to the lowest enlisted grade. The Court of Military Review affirmed the findings and sentence in an unpublished opinion on September 22, 1993.
4. We granted review on March 25, 1994, of the following issue:
WHETHER THE AIR FORCE COURT OF MILITARY REVIEW ERRED WHEN THEY REVERSED THE DECISION OF THE MILITARY JUDGE, WHO ORDERED A RETEST OF APPELLANT’S URINE SAMPLE FOR BENZOYLECGONINE (BE), ECGONI-NEMETHYLESTER (EME), AND RAW COCAINE.
5. We hold that the military judge did not abuse his discretion in his ruling and that the court below erred when they reversed that ruling.
Factual Background
6. Appellant asked the military judge to order a retest of his urine sample after the convening authority had denied the request. Appellate Exhibit II. The Government’s Response is App. Ex. III. Appellant asserted two bases for his request: “fairness and to avoid retrying this case at a later date.” Appellant argued that his “extremely low level (223 ng/ml)” (nanograms per milliliter) was close enough to the Department of Defense cutoff level of 150 ng/ml to warrant retesting.
7. In support of the request for retesting, defense counsel presented the testimony of Dr. John Vasiliades, former Chief of Quality Assurance at the Air Force Drug Testing Laboratory, who was accepted by both sides as an expert in forensic toxicology. Dr. Vasiliades testified that if a person ingested the normal recreational dose of cocaine, laboratory testing would reveal raw cocaine for about 10 hours, the EME metabolite for 40-48 hours, and the BE metabolite at the DoD (Dept, of Defense) cutoff level for about 72 hours. EME can only be produced by ingesting cocaine in the body; BE can be produced by placing cocaine directly into a urine sample. If a test is positive for BE but negative for EME, there are two possible explanations: (1) the person being tested “ingested cocaine” and “the EME has dissipated”; or (2) someone “put cocaine in the urine” sample “aside from ingestion.” The presence of BE and raw cocaine but no EME in the urine sample would indicate that someone “spiked” the urine sample.
8. Dr. Vasiliades testified that testing for EME and raw cocaine could be done “within one day” and “should not cost more than a couple of hundred dollars.” In documents attached to the written motion, defense counsel had represented that Northwest Toxicology Laboratory in Salt Lake City, Utah, a DoD certified laboratory, could conduct the EME testing at a cost of $150.00.
9. Finally, Dr. Vasiliades testified that, based on his previous experience at the Air Force Laboratory, appellant’s urine sample *302should have been frozen and retained, and thus was available for further testing. Dr. Vasiliades was asked if the sample would be “frozen in time” and the breakdown of the sample would be “minimal.” He responded in the affirmative, but qualified his answer by-testifying that “the only way we would know that is by retest.”
10. Trial counsel presented the testimony of Dr. Donald L. Frederick, current Chief of Quality Assurance at the Air Force Drug Testing Laboratory. Dr. Frederick testified, “I don’t think it is an absolute” that the presence of raw cocaine but the absence of EME would indicate a “spiked” sample. He explained that “some people that have atypical enzymes in their body and their processing of that compound would not be the same as the majority of us,” and therefore EME “may not be present or may be present in such a low level that you wouldn’t see it----”
11. Dr. Frederick agreed with Dr. Vasiliades, however, that testing for EME would provide more information and greater certainty “about how much cocaine was ingested or what time frame the cocaine was ingested in[.]” Dr. Frederick testified that the cost for a retest for raw cocaine, BE, and EME would be “probably in the range of $250.00.”
12. The military judge granted the defense request for retesting. After trial counsel announced that the convening authority would not order the retest, the military judge abated the proceedings.
13. The military judge’s written findings of fact include the following:
(1) Appellant’s urine contained a concentration of 223 ng/ml of BE.
(2) Assuming the normal recreational dose of 100 mg of cocaine, “BE will be detectable in the urine up to approximately 72 hours, and EME will be detectable in the urine up to approximately 40^8 hours.”
(3) “BE can be produced by ingesting cocaine or by putting cocaine in urine with the right PH balance; EME can be produced only through ingestion.”
(4) “By testing for EME and cocaine in conjunction with the BE test, a qualified forensic toxicologist can, with a reasonable degree of certainty, determine whether the cocaine in the urine was ingested by the accused or was placed in the urine from an outside source, either through intentional or unintentional contamination of the sample.”
(5) Appellant has no evidence of a break in the chain of custody.
(6) Appellant has no evidence of contamination of his urine sample.
(7) “Testing for BE, EME, and cocaine is a relatively simple procedure” that “will cost the government approximately $250.00.”
14. In his conclusions of law, the military judge stated that the results of EME testing would be relevant and that such evidence is “necessary” within the meaning of RCM 703(f)(1), Manual for Courts-Martial, United States, 1984. He concluded by observing, “Indeed, this may be the only way that an accused can effectively challenge the Government’s evidence on chain of custody, since an accused is at somewhat of a disadvantage in demonstrating intentional contamination of his sample or unintentional contamination in the testing process.”
15. After the Court of Military Review reversed the order of the military judge, the prosecution presented the test results and the stipulated testimony of the persons who obtained appellant’s urine sample. The defense ease consisted of the stipulated testimony of appellant’s superiors and peers, who stated that they were shocked when learning that appellant’s urinalysis was positive and they believed that appellant is a truthful person. Then, appellant testified that he did not “knowingly use cocaine” and had no idea how his sample could have tested positive.
Discussion
16. RCM 703(f)(1), relied upon by the military judge, provides: “Each party is entitled to the production of evidence which is relevant and necessary.” The term “necessary” means that the evidence “is not cumulative and ... would contribute to a party’s presentation of the case in some positive way on a matter in issue.” RCM 703(f)(1), Discussion.
*30317. The Court of Military Review held that the military judge’s reliance on RCM 708(f)(1) “was erroneous and led to the wrong result.” The court stated that RCM 708(f)(1) applies to “a party’s right to evidence already in existence—not ... evidence ... yet to be created.” 34 MJ at 1059. The court below held that appellant’s request should have been treated as a request for investigative or expert assistance and that the burden was on appellant to demonstrate the necessity for such assistance. 34 MJ at 1060. See United States v. Garries, 22 MJ 288, 290 (CMA), cert. denied, 479 U.S. 985, 107 S.Ct. 575, 93 L.Ed.2d 578 (1986).
18. The standard for reviewing a military judge’s decision to order the production of additional evidence is abuse of discretion. See United States v. Lampani, 14 MJ 22, 26 (CMA 1982). We previously have described the standard for reviewing a military judge’s exercise of discretion as follows:
To reverse for “an abuse of discretion involves far more than a difference in ... opinion____ The challenged action must ... be found to be ‘arbitrary, fanciful, clearly unreasonable,’ or ‘clearly erroneous’ in order to be invalidated on appeal.”
United States v. Travers, 25 MJ 61, 62 (CMA 1987), quoting United States v. Yoakum, 8 MJ 763, 768 (ACMR 1980) (quoting United States v. Glenn, 473 F.2d 191, 196 (DC Cir. 1972)), Yoakum aff'd on other grounds, 9 MJ 417 (CMA 1980).
19. In our view, the court below erred by applying the wrong standard. The defense did not assert that they were entitled to a retest under Garries, and the military judge did not base his ruling on a showing of necessity under Garries. The military judge granted the request on the basis of fundamental fairness, relevance, and the minimal burden on the Government. The question is whether he abused his discretion by granting the request even if the defense showing of necessity fell short of the Garries standard.
20. A military judge enjoys broad discretion on evidentiary and procedural matters. RCM 801 authorizes the military judge to “direct trial counsel to make an inquiry along certain lines to discover and produce additional evidence.” RCM 801(c), Discussion. Similarly, Mil.R.Evid. 614(a), Manual, supra, allows a military judge to sua sponte call witnesses.
21. This ease falls into the middle ground where the military judge may not be required, as a matter of law, to grant a defense request, but where he does not exceed the limits of his discretion by doing so. Even assuming that the retest may not have been “necessary” within the meaning of Garries, it certainly would have been helpful to the trier of fact. If it showed contamination of the sample, it would have supported the defense. If it failed to show contamination, it would have bolstered the prosecution. The burden imposed on the Government by retesting was minimal, in terms of time and resources.2
22. Although the military judge cited RCM 703(f)(1) to support his ruling, his findings of fact and conclusions of law are keyed to the grounds urged by the defense: fundamental fairness, relevance, and the minimal burden on the Government. Once the military judge exercised his discretion, the burden was on the Government to present “conclusive argument that the judge abused his discretion.” United States v. Mukes, 18 MJ 358, 359 (CMA 1984). We need not decide whether the military judge was required as a matter of law to grant the defense request. We hold only that he did not abuse his discretion by doing so. Cf. United States v. Robinson, 39 MJ 88, 89 (CMA 1994) (military judge did not abuse discretion by denying request for additional testing).3
*304The decision of the United States Air Force Court of Military Review is reversed. The findings of guilty and the sentence are set aside. The record of trial is returned to the Judge Advocate General of the Air Force. A rehearing may be ordered, subject to the military judge’s abatement order.
Judges COX and WISS concur.. See 41 MJ 213, 229 n. 1 (1994).
. Appellant asserted at trial and continues to assert on appeal, without contradiction from the Government, that he is indigent and cannot afford to pay for a retest. We find it somewhat ironic that the Air Force has spent 3 years litigating its refusal to conduct a simple $250.00 test.
. We respectfully disagree with Judge Crawford’s reliance on RCM 701(b)(2), Manual for Courts-Martial, United States, 1984 (1994 ed.). The rule requires that notice of intent to present an innocent-ingestion defense be given "before the beginning of the trial on the merits.” In this case *304file trial on the merits had not yet begun when the military judge ordered additional testing.