OPINION Appellant, Consuelo Cervantes, brought an action against El Paso Healthcare System, Ltd. d/b/a/ Del Sol Medical Center, Appellee (Del Sol), for violations of 42 U.S.C. § 1395dd, also known as the Emergency Medical Treatment and Active Labor Act (EMTALA). In a single issue, Appellant challenges the trial court’s grant of Del Sol’s motion for summary judgment. We affirm. BACKGROUND Factual Background According to Cervantes’ petition, on April 9, 2016, at 7:12 p.m., Cervantes’ medical records reveal she sought emergency care for abdominal pain at Del Sol. Cervantes was seen by Dr. Shariq Khan. Cervantes was physically examined and laboratory tests were ordered to include a CT scan of her abdomen. The CT scan revealed Cervantes had a recurrent ventral hernia containing bowel loops. Cervantes was treated with Valium and an intravenous solution of Sodium Chloride and Hydromorphone. It was determined Cervantes’ condition was stable and improved. Cervantes was then discharged April 9th from Del Sol at 9:46 p.m. with prescriptions for Tramadol and Zofran. In her petition, Cervantes alleged she returned to Del Sol’s emergency department, a little over four hours later, at 1:49 a.m. on April 10th complaining of abdominal pain. Her medical records indicate her pain level was nine out of ten and the prescribed medications were not working. Dr. Khan reviewed her prior laboratory tests and CT scan and screened Cervantes again. Based on his second screening, Dr. Khan ruled out an impression of an incarcerated umbilical hernia. Cervantes’ family requested her transfer to Sierra Providence East, the hospital where Dr. Jaime Gomez, the surgeon who performed her prior hernia repair, could see her. Finding Cervantes’ condition stable, Del Sol attempted to arrange the transfer, but it was denied. On April 10th Cervantes was released from Del Sol at 6:32 a.m. with instructions to see Dr. Gomez at Sierra Providence upon discharge. Cervantes’ petition alleges she arrived at Sierra Providence at 6:59 a.m. on April 10th. She further alleges she was suffering from shock and sepsis. Cervantes states she was eventually admitted to the intensive care unit at Sierra Providence and underwent surgery due to a perforated bowel. Lastly, she alleges she was hospitalized until May 19, 2016, and then transferred to a rehabilitation hospital where she remained until July 2016. Procedural Background On December 1, 2017, Cervantes filed suit in the El Paso County Court at Law Number Three asserting Del Sol violated the EMTALA on April 10, 2016. On April 2, 2018, Cervantes also filed a lawsuit in the United States District Court for the Western District of Texas asserting Del Sol violated the EMTALA on April 9, 2016. On May 2, 2019, the federal lawsuit was dismissed. Cervantes appealed and on November 21, 2019, the United States Court of Appeals, Fifth Circuit, affirmed the dismissal, finding no EMTALA violation for the April 9, 2016, emergency room visit. On May 7, 2020, in the trial court below, Del Sol filed its motion for summary judgment pursuant to Rule 166a asserting res judicata barred Cervantes’ claims. The motion for summary judgment was granted on September 15, 2020, by the trial court. Cervantes filed a motion for new trial on October 15, 2020. On November 12, 2020, this appeal followed. Procedural Decisions The issue before both the United States District Court for the Western District of Texas and the United States Court of Appeals, Fifth Circuit, was whether the EMTALA was violated by Del Sol’s alleged inappropriate medical screening examination and wrongful discharge of Cervantes. See Cervantes v. El Paso Healthcare Sys. Ltd., No. EP-18-CV-111-PRM, 2019 WL 1865285 at *1 (W.D. Tex. Apr. 25, 2019); Cervantes v. El Paso Healthcare System, 791 F. App’x. 470, 471-72 (5th Cir. 2019). Cervantes alleged she had an emergency medical condition and the EMTALA requires hospitals to conduct appropriate medical screening examinations to determine whether patients are suffering a medical emergency before discharge, therefore, Del Sol violated the EMTALA. See 42 U.S.C. § 1395dd(a).[1] The federal trial court granted Del Sol’s motion for summary judgment finding Cervantes cited to no evidence suggesting her screening failed to comply with Del Sol’s standard screening procedure, was different than screenings patients with similar symptoms received, or was so cursory it amounted to no screening at all. Cervantes, 2019 WL 1865285 at *10. The Fifth Circuit Court of Appeals affirmed on the same basis, holding the trial court correctly determined Del Sol did not violate the EMTALA because “[a] physician’s misdiagnosis, even if it could constitute negligence or medical malpractice, does not create an EMTALA claim.” Cervantes, 791 F. App’x. at 473. DISCUSSION Issue On appeal, Cervantes asserts the trial court erred in granting Del Sol’s motion for summary judgment. The crux of the issue on appeal is whether Cervantes’ state court lawsuit is barred by res judicata as the result of the federal court judgment. Standard of Review and Applicable Law We review the trial court’s summary judgment de novo. Ferguson v. Bldg. Materials Corp. of Am., 295 S.W.3d 642, 644 (Tex. 2009) (per curiam). To be entitled to summary judgment under Rule 166a, a movant must establish there is no genuine issue of material fact so that the movant is entitled to judgment as a matter of law. TEX.R.CIV.P. 166a(c); Mann Frankfort Stein & Lipp Advisors, Inc. v. Fielding, 289 S.W.3d 844, 848 (Tex.2009). Res judicata is an affirmative defense. A defendant moving for summary judgment on its affirmative defense must conclusively prove each element of that defense. See Shah v. Moss, 67 S.W.3d 836, 842 (Tex. 2001). Federal law controls the determination of whether the federal court’s judgment should bar Cervantes’ state court suit. See San Antonio Indep. Sch. Dist. v. McKinney, 936 S.W.2d 279, 281 (Tex. 1996)(noting that because the first suit was decided in federal court, federal res judicata law controls); Eagle Props., Ltd. v. Scharbauer, 807 S.W.2d 714, 718 (Tex. 1990)(same). “The res judicata effect of a prior judgment is a question of law that we review de novo.” Oreck Direct, LLC v. Dyson, Inc., 560 F.3d 398, 401 (5th Cir. 2009)(quoting Davis v. Dallas Area Rapid Transit, 383 F.3d 309, 313 (5th Cir. 2004)). “Under federal law, the doctrine of res judicata will apply if: (1) the parties are identical in both suits; (2) the prior judgment is rendered by a court of competent jurisdiction; (3) there is a final judgment on the merits; and (4) the same cause of action is involved in both cases.” Eagle Props., 807 S.W.2d at 718 (citing Nilsen v. City of Moss Point, 701 F.2d 556, 559 (5th Cir. 1983)); Clear Lake Ctr., L.P. v. Garden Ridge, L.P., 416 S.W.3d 527, 540-41 (Tex.App.—Houston [14th Dist.] 2013, no pet.). “Res judicata ‘bars all claims that were or could have been advanced in support of the cause of action on the occasion of its former adjudication, . . . not merely those that were adjudicated.’” In re Howe, 913 F.2d 1138, 1144 (5th Cir. 1990)(quoting Nilsen, 701 F.2d at 560). In determining whether two lawsuits involve the same claim or cause of action, federal courts utilize what is known as the transactional test. See Test Masters Educational Services, Inc., v. Singh, 428 F.3d 559, 571 (5th Cir. 2005). “Under the transactional test, a prior judgment’s preclusive effect extends to all rights of the plaintiff with respect to all or any part of the transaction, or series of connected transactions, out of which the original action arose.” Id. The critical question is whether the plaintiff bases the two actions on the “same nucleus of operative facts.” Id. (quoting New York Life Ins. Co. v. Gillispie, 203 F.3d 384, 387 (5th Cir. 2000)). Analysis The parties are identical in both lawsuits against Del Sol, the prior judgment was rendered by a court of competent jurisdiction, and the prior action was concluded by a final judgment on the merits. See Test Masters Educ. Servs., Inc., 428 F.3d at 571. Thus, only one of the four federal res judicata elements is at issue; the contested inquiry here is whether the same claim or cause of action is involved in both lawsuits. See id. In her First Amended Petition, Cervantes alleged as follows: Plaintiff brings this suit pursuant to 42 U.S.C. § 1395dd, also known as the Federal Emergency Medical Treatment and Active Labor Act (hereinafter referred to an “EMTALA”). Del Sol Medical Center is a participating hospital within the meaning of 42 U.S.C. § 1395dd (e) and all times material to the allegation in this Petition had a hospital emergency department. On April 9, 2016, at 7:12 p.m., Consuelo Cervantes sought emergency care at Del Sol’s emergency department [for] abdominal pain. She was found to have a recurrent ventral hernia containing loops. Plaintiff was discharged from the emergency department at 9:46 pm still in pain. On April 10, 2016, at 1:49 a.m., Consuelo Cervantes sought emergency care at Del Sol’s emergency department [for] abdominal pain. At that time she reported her pain level to be 9 out of 10. She was found to have a non-reducible supraumbilical hernia. On April 10, 2016, Plaintiff was not provided with an appropriate medical screening examination at Del Sol to determine if she had an emergency medical condition. Plaintiff was advised to seek care at another hospital where her surgeon had privileges. She was discharged at 6:32 a.m. Consuelo Cervantes arrived at the emergency department of The Hospitals of Providence East Campus at 6:59 a.m. At that time her vital signs indicated she was in shock. At The Hospitals of Providence East Campus plaintiff was found to have a perforated bowel that caused her to develop sepsis. She underwent surgeries and had a long and complicated hospital stay. Plaintiff was discharged on May 15th and transferred to a nursing facility. Cervantes asserted Del Sol’s alleged EMTALA violation on April 10, 2016, was a proximate cause of the following injuries and damages: physical pain and suffering; mental anguish; loss of income; medical expenses; deconditioning and physical impairment; and decreased life expectancy. Cervantes’ federal lawsuit, alleged, in part: Del Sol is a participating hospital within the meaning of 42 U.S.C. §1395dd(e) and all times material to the allegation in this Petition had a hospital emergency department. On April 9, 2016, at 7:12 p.m., Consuelo Cervantes sought emergency care at Del Sol’s emergency department for abdominal pain. At that time, she reported her pain level to be 9 out of 10. . . . On April 9, 2016, at 9:46 p.m., Plaintiff had an emergency medical condition but was discharged in a painful, unstable condition in violation of EMTALA. On April 10, 2016, at 1:49 a.m., Consuelo Cervantes returned to the emergency department at Del Sol for abdominal pain. Plaintiff was advised to seek care at another hospital where her surgeon had privileges. She was discharged at 6:32 a.m. Consuelo Cervantes arrived at the emergency department of The Hospitals of Providence East Campus at 6:59 a.m. At that time, her vital signs indicated she was in shock. At The Hospitals of Providence East, Plaintiff was found to have a perforated bowel that caused her to develop sepsis. She underwent surgeries and had a long and complicated hospital stay. She was discharged on May 15, 2016, and transferred to a nursing facility where she remained until mid-July, 2016. Cervantes’ federal lawsuit petition alleged Del Sol’s EMTALA violation on April 9, 2016, was the proximate cause of the following injuries and damages: physical pain and suffering; mental anguish; loss of income; medical expenses; deconditioning and physical impairment; and decreased life expectancy. On appeal, Cervantes argues the nucleus of facts between the two visits are not the same and maintains they constituted two separate and distinct encounters at Del Sol. Cervantes heavily relies on the creation of two sets of medical records for the two different visits to avoid the res judicata claim. As set out above, careful examination of both petitions plainly shows Cervantes asserted the same set of facts that formed the basis of her federal and state lawsuits. Under the transactional test, “[i]f the factual scenario of the actions parallel, the same cause of action is involved in both.” Agrilectric Power Partners, Ltd. v. General Elec. Co., 20 F.3d 663, 665 (5th Cir. 1994). Specifically, What factual grouping constitutes a “transaction”, and what groupings constitute a “series”, are to be determined pragmatically, giving weight to such considerations as whether the facts are related in time, space, origin, or motivation, whether they form a convenient trial unit, and whether their treatment as a unit conforms to the parties’ expectations or business understanding or usage. Petro-Hunt, L.L.C., v. United States, 365 F.3d 385, 396 (5th Cir. 2004)(quoting RESTATEMENT (SECOND) OF JUDGMENTS § 22(2) (AM. LAW INST. 1982)). Cervantes first sought emergency care at Del Sol at 7:12 p.m. on April 9, 2016. She was examined and laboratory tests were ordered, including a CT scan of her abdomen. After determining she was stable, Cervantes was discharged at 9:46 p.m. At 1:49 a.m. of that same night, albeit the next day and four hours later, Cervantes returned to the Del Sol emergency room complaining of persisting abdominal pain. Cervantes’ prior laboratory tests and CT scan were reviewed, and she was screened a second time. After determining Cervantes was stable, she was discharged a second time at 6:32 a.m. Cervantes alleged she arrived at Sierra Providence at 6:59 a.m. on April 10th where she remained hospitalized until May 19, 2016. Cervantes petition stated after her discharge she was transferred to a rehabilitation hospital where she remained until mid- July 2016. The two visits were separated by a little over four hours and both Cervantes’ federal and state lawsuits alleged the same misconduct and the same injury—Del Sol’s failure to provide an appropriate screening examination of her abdominal pain. She alleges the inappropriate screening which failed to diagnose her perforated bowel caused Cervantes to develop sepsis. Cervantes’ suits both rely on the alleged inappropriate medical screenings of April 9th and April 10th. We find the factual scenario of the situation in the lawsuits to be identical. The two separate dates, which are separated by four hours, do not make the transactions separate; the factual assertions in the federal and state lawsuits are part of the same series of connected transactions that resulted in a single, indivisible injury. See Nilsen, 701 F.2d at 564 (5th Cir. 1983)(“When two successive suits seek recovery for the same injury, ‘a judgment on the merits operates as a bar to the later suit, even though a different legal theory of recovery is advanced in the second suit.’”)(quoting Cemer v. Marathon Oil Co., 583 F.2d 830, 832 (6th Cir. 1978)). Here, in the federal and state lawsuits, (1) the parties are identical; (2) the same claim or cause of action is involved in both suits; (3) the prior judgment is rendered by a court of competent jurisdiction; and (4) the prior action was concluded by a final judgment on the merits. See Test Masters Educ. Servs., Inc. v. Singh, 428 F.3d at 571. We find the same claim or cause of action is involved in both lawsuits because the nucleus of operative facts for each lawsuit is parallel. Thus, all four federal res judicata elements are satisfied and Cervantes’ state proceeding is barred by the doctrine of res judicata. Del Sol has met its burden of demonstrating the absence of a genuine issue of material fact. See FM Props. Operating Co. v. City of Austin, 22 S.W.3d 868, 872 (Tex. 2000)(“When a trial court’s order granting summary judgment does not specify the grounds relied upon, the reviewing court must affirm summary judgment if any of the summary judgment grounds are meritorious.”). Accordingly, the trial court did not error in granting Del Sol’s motion for summary judgment. Appellant’s sole issue is overruled. CONCLUSION Having overruled the Appellant’s sole issue on appeal, we affirm the judgment of the trial court. YVONNE T. RODRIGUEZ, Chief Justice April 8, 2022 Before Rodriguez, C.J., Palafox, and Marion, C.J. (Ret.) Marion, C.J. (Ret.)(Sitting by Assignment)