A jury convicted the defendant on two indictments charging rape of a child and two indictments charging indecent assault and battery on a child. The complainant was *804his younger daughter, thirteen years of age at the time of the incident. The defendant appealed, claiming that a judge in the Superior Court who ruled on certain pretrial motions erroneously had barred him access to potentially exculpatory evidence. He also claims that the judge who presided at his trial erroneously prevented him from presenting evidence tending to show his innocence. We granted the defendant’s application for direct appellate review. We reverse the judgments, set aside the defendant’s convictions and remand the case to the Superior Court for further proceedings consistent with this opinion.
1. Background. We first summarize the evidence at trial, leaving for later discussion particular facts concerning the defendant’s appellate claims.
The defendant is a divorced father of four children. He lived with his parents (the children’s grandparents) and his older daughter, Alison,1 who was twenty years of age at the time of trial. The defendant’s three other children, Benjamin, seventeen years old at the time of the alleged incident, and Eric and Ellen, twins, thirteen years old at the time of the alleged incident, lived primarily with their mother, but stayed with the defendant and their grandparents every other weekend.
On Saturday, March 3, 2001, the defendant and his four children attended a party to celebrate the grandparents’ fiftieth wedding anniversary. On returning home, the defendant, Benjamin, Eric, and Ellen all went upstairs. Approximately one-half hour later, Ellen came downstairs, telling her grandparents that the defendant had “tried to rape” her, but that she had “punched him in the eye” and run away. The grandfather went upstairs to confront the defendant with the child’s accusation.
Ellen testified that the defendant had found her lying fully clothed on Alison’s bed, in a bedroom where Ellen often slept. She testified that the defendant “unzipped his pants[,] moved [her] underwear over,” and placed the tip of his penis into her vagina. She then “flipped him over onto his back,” she said, punched him in the eye, and ran downstairs.2
The defendant testified to a quite different set of events. He *805said that he was in the bathroom at the time of the alleged assault and emerged only to have Ellen punch him in the eye for no apparent reason.3 No witness could corroborate either account of what transpired on the night of March 3. However, there was testimony by her siblings and her grandmother tending to contradict certain of Ellen’s claims. The next morning the defendant informed the police of Ellen’s accusations against him, and he consistently has denied any inappropriate behavior toward Ellen that evening, or at any other time.
There was testimony from several witnesses that Ellen was a very emotional child who had difficulty interacting with other members of her family. Her grandmother attempted to take Ellen to a hospital emergency room immediately after her accusation of rape; Ellen refused to go. Shortly thereafter, Ellen returned to her mother’s home. The following morning, her mother took Ellen to a hospital, where Ellen repeated her accusation against her father and was examined by a doctor and a nurse. The examination uncovered no physical evidence connected to the defendant, but during a pelvic examination, the nurse noticed that Ellen’s vaginal wall was “redder than the normal,” a condition known as erythema. Ellen’s statements to her mother and the nurse were admitted as fresh complaint evidence. These were largely consistent with Ellen’s own testimony.
A gynecologist called as an expert for the defense testified that erythema of the type observed by the nurse was a “common” condition not “specific to a trauma of the vagina.” On cross-examination, the doctor did testify that erythema, while a “non-specific finding,” “could” result from sexual assault. In closing argument, the prosecutor characterized the nurse’s observation as “abnormal findings of [Ellen’s] vagina . . . *806abnormal redness of the vagina,” and argued that the finding of erythema in her vagina “can” mean “trauma from a sexual assault” and was “corroboration for what [Ellen] told you.”
2. Discussion. On appeal, the defendant does not challenge the evidence admitted at trial. Rather, he contends that the jury were not permitted to consider other admissible evidence that pointed to his innocence. We consider each of his claims in turn, and conclude that they are meritorious.
a. Pretrial discovery. The defendant’s first claim concerns a matter of pretrial discovery. Shortly after the defendant was indicted, defense counsel learned that the Commonwealth intended to introduce evidence gleaned from the complainant’s March 4, 2001, pelvic examination. Defense counsel later learned that Ellen had undergone a previous pelvic examination less than six weeks earlier, on January 22, 2001, also following an allegation that she had been sexually assaulted, this time while at school.4 The defendant moved for “the production of the medical records pertaining to a pelvic examination of [Ellen] on January 22, 2001.” Counsel did not know any specifics concerning the examination. In a separate written motion, he requested an order “directing] the Commonwealth to obtain and provide the name and address of [the] doctor who conducted a pelvic exam on [Ellen] on January 22, 2001 [,] as a result of an alleged sexual assault at her school.” A Superior Court judge held a nonevidentiary hearing on the motions, during which defense counsel stated that he sought the results of the January examination in order to allow a defense expert to assess the probative value of Ellen’s erythema identified during her second pelvic examination on March 4, and could be “important in terms of any physical feature, characteristic, or condition of the alleged victim . . . .” The judge denied the motions, ruling that *807defense counsel had failed to demonstrate a sufficient basis to require production.5
The defendant and the Commonwealth both recognize that the defendant’s motion for “the production of the medical records” was a motion for a summons for records from a third party, governed by Mass. R. Crim. P. 17 (a) (2), 378 Mass. 885 (1979). See Commonwealth v. Lampron, 441 Mass. 265, 268 (2004) (“Regardless of how a defendant styles his request, pursuit of documents and records in the possession of a non-party must be considered and analyzed under rule 17 [a] [2] . . .”). For reasons we now explain, we conclude that the defendant made a sufficient showing for the issuance of a summons.
A party moving to subpoena (summons) documents to be produced before trial “must establish good cause, satisfied by a showing ‘(1) that the documents are evidentiary and relevant; (2) that they are not otherwise procurable reasonably in advance of trial by exercise of due diligence; (3) that the party cannot properly prepare for trial without such production and inspection in advance of trial and that the failure to obtain such inspection may tend unreasonably to delay the trial; and (4) that the application [was] made in good faith and [was] not intended as a general “fishing expedition.” ’ ” Commonwealth v. Lampron, supra at 269, quoting United States v. Nixon, 418 U.S. 683, 699-700 (1974). In this case the Commonwealth challenges in substantial measure only whether the defendant has satisfied the first of the four prongs. Our inquiry therefore is whether the *808defendant has shown that records pertaining to the complainant’s January pelvic examination are “likely to be admissible at hearing or at trial,” Commonwealth v. Lampron, supra, citing Bowman Dairy Co. v. United States, 341 U.S. 214 (1951), and have a “rational tendency to prove [or disprove] an issue in the case,” Commonwealth v. Lampron, supra at 269-270, quoting Commonwealth v. Fayerweather, 406 Mass. 178, 183 (1989). See Commonwealth v. Lam, ante 224, 230 (2005), and cases cited. The Commonwealth does not question the admissibility of medical records but argues that defendant failed to show that the records meet the threshold of relevance.
Here, the records-of Ellen’s January pelvic examination bore on a critical fact in the defendant’s case: whether the erythema described by the nurse in March was corroborative of Ellen’s allegations against her father. If Ellen’s earlier pelvic examination had revealed erythema similar to (or more serious than) the erythema noted by the nurse in March, the Commonwealth’s theory that the March results were probative of sexual assault may have been significantly undercut. The prosecutor, for example, might not have been able to argue that Ellen’s vaginal condition on the morning after the alleged rape was “abnormal” for Ellen.6 A defendant is not required to state with certainty the precise maimer in which a medical record would be employed at trial. When a party cannot know for certain the contents of a requested document, it is appropriate for a court to order the issuance of a summons pursuant to rule 17 (a) (2) on a showing of the relevance of what the document is likely to contain. See United States v. Nixon, supra at 700.7 The January records likely would have given the jury a more comprehensive and fairer picture as to the significance of the March records to be *809introduced by the Commonwealth. A summons was appropriate. See Commonwealth v. Mitchell, ante 786, 795 (2005) (“A defendant has an unquestioned right ... to obtain relevant evidence that bears on the question of his guilt or innocence or which otherwise will help his defense”).
b. Evidence excluded at trial. The defendant next challenges an evidentiary ruling at trial. During its case-in-chief, the Commonwealth elicited testimony from a police officer that shortly after Ellen accused her father, her grandfather went upstairs to confront the defendant. The grounds for admission of this evidence are unclear, but no objection was made. Later in the trial, defense counsel called the grandfather as a witness and he testified to similar effect that, on hearing Ellen’s accusations, he went upstairs to confront his son and found the defendant “in the bathroom checking his eye.” He then testified:
“I banged on the door and I told him I wanted to talk to him. And I went into my bedroom. And he came out, and he came in, and I told him what [Ellen] had said and the look on his face was complete bewilderment. ... He didn’t realize what I was saying until I had to repeat myself.”
If permitted, the grandfather would have testified further that the defendant promptly and strongly denied Ellen’s accusations. The judge, however, on the Commonwealth’s objection, excluded the testimony, pointing to the hearsay rule. Defense counsel challenged the ruling on the ground that the defendant’s statement qualified as a spontaneous utterance, which the judge rejected.
On appeal the defendant now contends that his denial should have been admitted through the doctrine of “curative admissibility.” See Commonwealth v. Ruffen, 399 Mass. 811, 812-814 (1987). In the alternative, he argues that the judge abused her discretion in ruling that his denial to his father did not qualify as a spontaneous utterance. As we shall explain, we cannot conclude that the judge abused her discretion on the spontaneous utterance claim, but we agree with the defendant *810that the defendant’s denial should have been admitted under the doctrine of curative admissibility. Because the admission of the grandfather’s testimony was not sought on this basis, we review the judge’s decision to determine whether it created a substantial risk of a miscarriage of justice. See Commonwealth v. Freeman, 352 Mass. 556, 563-564 (1967).
We consider first the applicability of the doctrine of curative admissibility to this case. In Commonwealth v. Ruffen, supra, a judge erroneously, although without apparent objection, admitted in evidence the complainant’s face-to-face accusation of the defendant, which was made in the presence of a police officer. The judge then precluded the defendant from asking the police officer to testify concerning the defendant’s prompt denial of the accusation when confronted. Id. at 812. We held that, because the “jury heard the officer testify that the victim made an accusation by relating her story in front of the defendant ... the defendant should have been allowed, under the doctrine of curative admissibility, to present testimony that he denied the accusations.” Id. at 813.
The circumstances are the same here. Evidence of the grandfather’s out-of-court accusation of the defendant made in his presence should not have been admitted. See Commonwealth v. Ruffen, supra at 813; Commonwealth v. Cruz, 373 Mass. 676, 691 (1977) (“accusatory questions followed by unequivocal denials are to be excluded from evidence”); Commonwealth v. Locke, 335 Mass. 106, 115 (1956) (“It is settled that extrajudicial accusatory statements made in the presence of a defendant are not admissible as evidence against him where the defendant has denied the accusations”). We do not fault the judge on that point, because the defendant did not object to or move to strike the testimony. But once the jury heard the police officer’s testimony that the grandfather had accused the defendant, the judge should have allowed in evidence the defendant’s unequivocal denial, minimizing, as much as possible, the prejudice to the defendant of the earlier testimony. Commonwealth v. Ruffen, supra at 813-814.
In Commonwealth v. Ruffen, supra, we noted that the doctrine of curative admissibility may only be invoked “if the original evidence created significant prejudice.” Id. at 814. The Com*811monwealth argues that this is not such a case. The clear import of the Ruffen case, however, is that a defendant almost always suffers significant prejudice when he is unable to counter evidence of an out-of-court accusation made in his presence with evidence from a third party that the defendant promptly and completely denied the accusation. See Commonwealth v. Cruz, supra at 692. This case provides no exception to the general rule.
Other evidence elicited by the Commonwealth that, on the night of the incident, the defendant could be seen crying himself to sleep compounded the error. Without any information from the grandfather that the defendant had immediately denied his daughter’s accusations, the jury could well have concluded that the defendant was showing remorse after having been caught in the commission of a crime. See Commonwealth v. Keyes, 11 Gray 323, 324 (1858) (“whenever the statements, declarations or admissions of a party are made subjects of proof, all that was said by him at the same time and upon the same subject is admissible in his favor”). It was not sufficient for the judge to allow, as she did, the defendant himself to testify that he had denied the grandfather’s accusatory statement.8 See Commonwealth v. Britland, 300 Mass. 492, 496 (1938) (“Evidence of statements favorable to the defendant . . . coming from the defendant alone . . . might be viewed with the suspicion that they were of later invention”).
Because we conclude that the testimony should have been admitted under the doctrine of curative admissibility, we comment only briefly on the judge’s ruling on the spontaneous utterance exception to the hearsay rule. The test for admissibility under that exception has two prongs, both of which must be met for a statement to be admitted. First, a judge must determine whether the statement was triggered by an “event ‘sufficiently startling to render inoperative the normal reflective thought processes of the observer.’ ” Commonwealth v. Santiago, 437 *812Mass. 620, 623 (2002), quoting 2 McCormick, Evidence § 272, at 204 (5th ed. 1999). Second, a judge must consider whether the statement was a “spontaneous reaction to the . . . event” or more likely “the result of reflective thought.” Commonwealth v. Santiago, supra. Here, there was evidence sufficient to create a question under both prongs. The judge was warranted in asking, based on the facts presented, whether the grandfather’s accusation “ render [ed] inoperative” the defendant’s capacity for reflective thought. Similarly, the judge may have questioned whether the defendant’s opportunity to deliberate while the grandfather repeated Ellen’s accusation (for a duration not ascertainable from the record) supported a finding that the defendant had “time to contrive and misrepresent.” Commonwealth v. McLaughlin, 364 Mass. 211, 223 (1973), quoting J. Wigmore, Evidence § 1750 (3d ed. 1940). On the record at the time of her ruling, the judge would have been warranted in concluding that the questions defense counsel asked of the grandfather did not provide sufficient facts for her to conclude that both prongs of the test had been satisfied.
We consider now the effect of the judge’s ruling on the verdicts. We are not confronted in this case solely by the effect of the ruling concerning the grandfather’s excluded testimony. Rather, there were two separate errors that in combination, we conclude, deprived the defendant of the opportunity to develop his defense fully. See Commonwealth v. Bohannon, 376 Mass. 90, 94 (1978), S.C., 385 Mass. 733 (1982). On a review of the entire transcript, we are left with substantial concerns whether there has been a miscarriage of justice. A new trial is warranted.
Accordingly, the judgments are reversed, the verdicts set aside, and the case is remanded to the Superior Court for further proceedings consistent with this opinion.
So ordered.