OPINION
This is a suit against a blood bank resulting from the death of a blood recipient from acquired immunodeficiency syndrome (AIDS) and the subsequent AIDS infection of the recipient’s wife. The plaintiffs alleged that the blood bank negligently screened blood donors and tested blood donations for infection.
J.K. and Susie L. Wadley Research Institute and Blood Bank, d/b/a The Blood Center at Wadley (Wadley), appeals from a judgment in favor of appellees, Esther Bee-son, individually and as representative of the estate of Thomas W. Beeson, and Bruce Beeson (the Beesons), in the Bee-sons’ suit under the wrongful death and survival statutes. Wadley argues in three points of error that the trial court erred in denying its motion for judgment notwithstanding the verdict because (1) the Bee-sons’ wrongful death and survival causes of action are barred by the applicable statutes of limitations, (2) Esther’s personal injury claims are barred by the applicable statutes of limitations, and (3) the evidence is legally insufficient to support the jury verdict with regard to causation. For the reasons given below, we affirm the trial court’s judgment.
BACKGROUND FACTS
On April 22, 1983, Dr. William Kraus, a cardiologist, discovered that Tom had severe blockage of two major arteries in his heart and recommended cardiac bypass surgery. During surgery that same day, Tom received seven units of blood by transfusion. In late May 1987, Tom had trouble breathing and chest pain. He was hospitalized on June 5, 1987. Dr. Kraus consulted with two specialists in pulmonary medicine about the unusual pneumonia evident in x-rays of Tom’s lungs. Because there was a possibility that the lung infection was secondary to AIDS, Tom was tested for HIV. Although Tom had not been formally diagnosed, doctors empirically started him on therapy for AIDS on June 6, 1987. On June 9, 1987, Tom was formally diagnosed as HIV positive. Esther was then tested for HIV, and she learned in June 1987 that she was HIV positive. Tom died on July 2, 1987.
On April 21, 1989, Esther and her son, Bruce, filed suit against Wadley alleging that Tom contracted AIDS from the transfusion of a unit of blood donated at Wadley on April 19, 1983, by a donor identified at trial as John Doe. The parties stipulated at trial that Doe was a sexually active homosexual male with multiple sex partners. On June 7,1990, the Beesons amended their original petition to contend that Wadley’s negligence in testing and screening blood donors caused Esther’s contraction of AIDS. At trial, the jury awarded the Beesons $800,000 in damages. Following the trial court’s denial of Wadley’s motion for judgment n.o.v., Wadley filed this appeal.
STATUTE OF LIMITATIONS
A. Wrongful Death and Survival Claims
Wadley argues in its first point of error that the trial court erred in denying its *693 motion for judgment n.o.v. because the Beesons’ wrongful death and survival causes of action are barred by the applicable statutes of limitations. Wadley’s pleadings alleged that the Beesons’ claims were barred by the “statute of limitations pursuant to the Medical Liability and Insurance Improvement Act of Texas, art. 4590(i)” and by the “common law statute of limitations.”
Wadley first argues that Tom’s negligence cause of action is a claim for personal injuries barred by the two-year statute of limitations. Tex.Civ.PRAC. & Rem.Code Ann. § 16.003(a) (Vernon 1986). The Beesons respond that the allegation that their claims were barred by the “common law statute of limitations” was insufficient to raise the statute of limitations contained in section 16.003(a) as an affirmative defense because it failed to give them fair notice of Wadley’s defensive theory.
Schley v. Structural Metals, Inc.,
We agree that the defendant must state its affirmative defenses in sufficient detail to give the plaintiff fair notice of the defensive issues to be tried.
Hunter,
Wadley had the burden of proof on its limitations defense at trial.
Woods,
A cause of action generally accrues when the wrongful act effects an injury, regardless of when the plaintiff learned of the injury.
Robinson v. Weaver,
The Beesons reply that a cause of action accrues when, and only when, damages are sustained.
Atkins v. Crosland,
We agree that Tom did not suffer a legal injury at the time Wadley collected the contaminated blood because the collection itself did not invade any of his legally protected rights. Hence, Wadley’s negligent act was not in itself “unlawful” as to Tom, and his cause of action accrued when he sustained damages.
Atkins,
The Discovery Rule
The discovery rule represents an exception to the general rule that a cause of action accrues when the wrongful act effects an injury, regardless of when the plaintiff learned of the injury.
Moreno v. Sterling Drug, Inc.,
We first determine the applicability of the rule to our case. The supreme court has applied the discovery rule to a limited number of cases, including certain medical malpractice cases, in which the plaintiff did not, and could not, know of the injury at the time it occurred.
Moreno,
We next determine whether this rule is available to the Beesons to toll the running of limitations. Wadley argues that the discovery rule does not toll the statute of limitations in this case because the Beesons failed to plead, prove, and secure findings on the discovery rule.
Woods,
Next, the Beesons argue that they met their burden of proof under the discovery rule. They contend that they conclusively established that Tom and his family did not discover that he had contracted AIDS until he showed symptoms in May 1987 and received the formal diagnosis in June. They assert that because they conclusively established the discovery rule, they had no need to request issues or to obtain favorable findings thereon.
Wright v. Gifford-Hill & Co., Inc.,
There is no evidence in this record that Tom and his family discovered his AIDS infection prior to May 1987. Wadley conceded in oral argument that the Beesons did not discover the infection until 1987, but it argued that, to toll the limitations period, the Beesons had to secure favorable findings that Tom’s injury “with reasonable diligence could not have been discovered within the limitations period.” We conclude that Wadley misstates the requirements of the discovery rule. The rule tolls the limitations period until the time that the plaintiff discovered, or through the exercise of reasonable care and diligence should discover, the nature of his injury.
Weaver,
Wadley contends that Esther’s testimony raised a fact question of when a reasonable person should have discovered Tom’s infection. It relies on her testimony that she and Tom had discussed getting tested for AIDS because they knew “that they didn’t have a test for the blood in [19]83 as such and that there was a possibility that he could have gotten it in the blood transfusion.” However, in its motion for judgment n.o.v., Wadley alleged that the Bee-sons “did not adduce evidence at trial or request a jury question regarding when [they] discovered their cause of action.” Wadley neither raised the issue of when the Beesons should have discovered through reasonable diligence Tom’s injury nor argued this theory in its brief. We conclude that Wadley has not preserved its argument that there is a fact question about when Tom, as a reasonable person, should have discovered the infection.
Further, we also conclude that Tom’s and Esther’s general knowledge that there was a possibility that he had contracted AIDS from the 1983 blood transfusion, without more, amounted to no more than a scintilla of evidence on the issue of whether Tom should have investigated or made inquiry to see if he had in fact contracted HIY from that transfusion. There is no other evidence in the record to indicate that the Beesons discovered or should have discovered the infection prior to Tom’s symptoms appearing in May 1987, and it is undisputed that Tom did not in fact discover that he had HIV until June 1987. Accordingly, we hold that the Beesons conclusively proved *696 under the discovery rule that their cause of action accrued at the earliest in May 1987 when they were first put on notice by Tom’s symptoms of the nature of his injury. We further hold that, when the Bee-sons filed suit on April 21, 1989, they filed within the two-year statute of limitations period set forth in section 16.003(a) of the Texas Civil Practice and Remedies Code.
In the alternative, Wadley argues that Tom’s cause of action is barred by the two-year statute of limitations in section 10.01 of the Texas Medical Liability and Insurance Improvement Act. Tex.Rev.Civ. Stat.Ann. art. 4590i, § 10.01 (Vernon Supp. 1992). Section 10.01 provides that no health care liability claim may be commenced unless suit is filed within two years from the occurrence of the breach. Wad-ley contends that it is entitled to assert this two-year statute of limitations as a bar to the Beesons’ cause of action because it is a health care provider that provides services to patients through hospitals. Wadley’s argument is premised on its qualification as a health care provider as defined in the Texas Medical Liability and Insurance Improvement Act. Tex.Rev.Civ.Stat.Ann. art. 4590i, § 1.03(a)(3) (Vernon Supp.1992). A health care provider is defined as follows:
any person, partnership, professional association, corporation, facility, or institution duly licensed or chartered by the State of Texas to provide health care as a registered nurse, hospital, dentist, podiatrist, pharmacist, or nursing home, or an officer, employee, or agent thereof acting in the course and scope of employment.
Id. (emphasis added). Wadley does not provide health care in any capacity listed in section 1.03(a)(3). Wadley also does not meet the definition of a hospital in section 1.03(a)(5). See Tex.Rev.Civ.Stat.Ann. art. 4590i, § 1.03(a)(5). Further, a health care liability claim is based on treatment, lack of treatment, or departure from accepted standards of medical or health care. Tex. Rev.Civ.Stat.Ann. art. 4590i, § 1.03(a)(4) (Vernon Supp.1992). A blood bank does not provide medical or health care to the blood transfusion recipient. Thus, we conclude that Wadley is not covered by the provisions of the Medical Liability and Insurance Improvement Act and cannot assert the limitations provision in section 10.01 to bar the Beesons’ wrongful death and survival causes of action.
Finally, Wadley argues that Esther’s and Bruce’s causes of action are barred because their recovery is authorized only if Tom would have been entitled to bring suit. Tex.Civ.Prac. & Rem.Code Ann. § 71.003(a) (Vernon 1986). This contention is untenable because we have overruled its premise. Tom is entitled to bring suit and, therefore, Esther and Bruce are authorized to recover under section 71.003(a). Id. Accordingly, we overrule Wadley’s first point of error.
B. Personal Injury Claims
In its second point of error, Wadley argues that the trial court erred in denying its motion for judgment n.o.v. because Esther’s personal injury claim is barred by the applicable statute of limitations. Wad-ley contends that Esther’s cause of action is time-barred because it was not brought until more than two years after the latest possible date that her cause of action accrued. Tex.Civ.PRAc. & Rem.Code Ann. § 16.003(a) (Vernon 1986). The record reflects that Esther learned of her HIV infection in June 1987 and amended the pleading on June 5, 1990, to assert that Wadley’s negligence proximately caused her personal injuries.
In appropriate circumstances, amended and supplemental pleadings relate back to the filing of the original pleading. Tex.Civ.PRAC. & Rem.Code Ann. § 16.068 (Vernon 1986). Section 16.068 provides as follows:
If a filed pleading relates to a cause of action, cross action, counterclaim, or defense that is not subject to a plea of limitation when the pleading is filed, a subsequent amendment or supplement to the pleading that changes the facts or grounds of liability or defense is not subject to a plea of limitation unless the amendment or supplement is wholly *697 based on a new, distinct, or different transaction or occurrence.
Id.
Thus, an amended pleading alleging a new cause of action relates back to the original filing and is not subject to a limitations defense if the original pleading was filed within the limitations period and if the amendment is not based on a wholly new, distinct, or different transaction.
Leonard v. Texaco, Inc.,
Wadley relies on
Harris v. Galveston County,
Under the facts of our case, however, Esther’s personal injury cause of action is based on Wadley’s negligence at the time of the blood donation on April 19, 1983. She does not assert that Wadley’s negligence occurred at the unknown time of the sexual transmission of HIV from Tom to her. The original petition and the amendment concerning Esther’s personal injury claim are based on the same transaction— Wadley’s negligent collection of blood donations. Thus, we conclude that Esther’s personal injury cause of action relates back to the filing of the original petition on April 21,1989, and is not barred by the statute of limitations. Accordingly, we overrule Wad-ley’s second point of error.
CAUSATION
Wadley argues in its final point of error that the trial court erred in denying Wad-ley’s motion for judgment n.o.v. because the evidence of causation is legally insufficient to support the jury verdict. Wadley contends that the Beesons failed to prove that Doe, the donor, would not have donated blood on April 19, 1983, if Wadley had implemented the screening procedures and blood tests advocated by the Beesons. The Beesons assert that there is competent evidence to support the jury’s answers to the causation questions.
Wadley’s complaint raising legal insufficiency is a “no evidence” point of error.
Croucher v. Croucher,
*698
Proximate cause includes two essential elements: (1) foreseeability and (2) cause-in-fact.
Exxon Corp. v. Quinn,
The question of causation is a fact question for the jury.
Farley v. M.M. Cattle Co.,
Wadley argues that the Beesons’ proof of causation is legally insufficient because they failed to prove that: (1) Tom was infected by a blood transfusion from Wad-ley rather than from other sources; (2) Doe would not have donated blood had a different acknowledgement form been used; (3) Doe would have answered affirmatively in April 1983 if directly questioned about his sexual preference, history, and practices, thereby resulting in his deferment as a blood donor; (4) Doe would not have given blood if different language had been used to describe high-risk groups on the AIDS information sheet; (5) the hepatitis B core antibody was an effective surrogate test for AIDS and that Doe would have tested positive to the test in April 1983, excluding his blood from use for transfusion; and (6) a reasonable blood bank could have foreseen that the use of semantic differences on the acknowledgement forms and AIDS information sheets, the refusal to use direct questions regarding sexual behavior, or the refusal to use the hepatitis B core antibody test would in reasonable probability present a danger to others.
The first five items complain of lack of evidence to prove cause in fact and the sixth complains of no evidence to prove foreseeability. We agree with the Beesons that lack of direct evidence on causation in this case does not amount to legally insufficient evidence of causation. Here, as in LaQuinta-Redbird, there is no direct proof of proximate cause or lack of proximate cause, and there is no way to prove by direct evidence that better procedures and donor education would have changed the result of Doe’s visit to Wadley to donate blood in April 1983. Thus, we must examine the record to determine whether there is more than a scintilla of probative evidence of a causal relationship between the transfusion that Tom received and his HIV infection, and more than a scintilla that it was foreseeable that Wadley’s conduct in April 1983 could lead to the sale of AIDS-contaminated blood.
We note that Wadley’s arguments to support lack of evidence of causation are based in large part on evidence and inferences that do not support the jury findings, while we can consider only evidence and
*699
reasonable inferences tending to support those findings. Thus we must disregard much of the evidence relied on by Wadley.
Responsive Terminal Sys., Inc.,
After a careful review of the entire record, we conclude that there is legally sufficient evidence to support the jury’s finding that Wadley’s negligence was a proximate cause of the Beesons’ damages. The possibility of AIDS transmission through blood or blood products was raised in mid-1982 as a result of several AIDS cases among hemophiliacs. By January 1983, Wadley knew that AIDS was a “major blood banking issue”; that blood from homosexual or bisexual males should not be accepted under any circumstances; and that a “very significant” number of contaminated units of blood would be accepted if Wadley did not act appropriately. Wad-ley’s written policy was that “donors who volunteer that they are gay” should not be permitted to donate blood. In practice, however, Wadley eliminated only “sexually active homosexual men with multiple sexual partners.” Wadley knew that seventy to seventy-five percent of persons with AIDS were homosexuals and that it could eliminate seventy to seventy-five percent of the problems with AIDS-contaminated blood if it excluded all homosexual males as donors.
Wadley also was aware of statements on AIDS issued by the American Association of Blood Banks, the Community Council of Blood Centers, and the Centers for Disease Control in January and in March 1983. Both statements contained suggestions concerning questions for donor screening and recruitment. The January 1983 statement suggested that donor screening include specific questions concerning AIDS symptoms to -identify members of high-risk groups, that donor recruitment should not target high-risk groups, and that direct or indirect questions about a donor’s sexual preference were inappropriate and were justified only if they demonstrated clear-cut benefits. The March 1983 statement included a sample information sheet for distribution at the time of donation. The information sheet identified the high-risk groups, explained that AIDS may be spread through blood products and that there was no way to detect AIDS, and asked members of high-risk groups to voluntarily refrain from donating blood. It further required donors to sign an acknowledgment form stating that the donor had read and understood that members of the high-risk groups had been asked not to donate blood.
Wadley gave copies of the January and March 1983 statements to its donors and added a question to its donor source card to address symptoms indicative of AIDS. Linda Dianne Hall, Wadley’s former associate administrator, testified that the donor source card was on a clipboard and that the joint statements and AIDS information sheet were placed on top of the card. Wad-ley stamped the back of the donor source card with the donor’s acknowledgment that he had been provided with AIDS information. Hall explained that the donor screen-er had to inquire if the donor had read and understood the information before the donor signed the acknowledgment.
Wadley knew that the American Association of Blood Banks (AABB) recommended that prospective donors be asked directly whether they were a member of a high-risk group and that all those answering affirmatively be excluded. However, Wadley never directly asked donors if they were members of recognized high-risk groups or if they had close contact with such members. Wadley did not accept the AABB’s recommended donor acknowledgment form or the Food and Drug Administration’s “recommendations to decrease the risk of transmitting AIDS from blood donors,” which included specific questions designed *700 to detect possible AIDS symptoms or exposure to patients with AIDS. Further, Wad-ley’s donor acknowledgment was different from that developed by the AABB. The AABB form stated that the donor had read the AIDS literature and understood that members of high-risk groups were asked not to donate blood, whereas Wadley’s form required the donor to initial the statement stamped on the back of the donor source card that the donor had been provided with AIDS information. A donor was not specifically asked if he had read and understood the AIDS information or if he was a member of a high-risk group.
Doe voluntarily donated blood at Wadley on April 19, 1983, and had given blood at Wadley about once a year without any problem since the early 1970’s. Doe did not remember the donor screening procedures at Wadley in April 1983. Doe testified that he did not know that he was at high risk for AIDS, that he would never have given blood if he had known that he was at risk for AIDS, and that he always told the truth in response to Wadley’s questions of him. 1 We do not know whether Doe signed the AIDS information acknowledgment because we do not have a copy of the back of the card. 2
This evidence is some evidence that Wad-ley’s screening procedure did not effectively educate donors and that it would have received direct answers from Doe if it had asked specific questions. The jury could reasonably infer that Wadley’s failure to effectively educate Doe and to ask Doe specific questions caused him to donate blood rather than to defer. Further, the foregoing constitutes more than a scintilla of evidence to support a finding that Wad-ley, despite its knowledge about the dangers of AIDS-contaminated blood, failed to reject gay men; that donor screening was inadequate; and that these omissions were substantial factors in causing Tom’s and Esther’s HIV infections.
Likewise, there is evidence to support the Beesons’ surrogate testing theory even if we discount their expert’s testimony on this question. Wadley’s own expert, Dr. Herbert Polesky, admitted that more than two out of three sexually active homosexual males would have been excluded from the donor population through the use of the hepatitis B core antibody test. This constitutes scientific proof that there was a sixty-seven percent chance that Doe would have been excluded if such test had been used.
There is also some evidence that Doe’s blood contained AIDS. Wadley’s own technical director, Jerry Staples, admitted that there was “strong evidence” that the blood Wadley accepted from Doe on April 19, 1983, was contaminated with AIDS. This statement was based on the fact that Doe’s blood was broken into two components, with red blood cells given to Tom and fresh frozen plasma given to another recipient six months later, and that both Tom and the plasma recipient subsequently were diagnosed as HIV positive less than six months apart from one another.
In summary, our review of the evidence reveals that the jury could reasonably have concluded that Wadley’s negligence was a substantial factor in bringing about the Beesons’ injuries and without which no harm would have occurred.
McClure,
We affirm the judgment of the trial court.
Notes
. Doe testified that he did not realize that he was gay until 1985. Thus, he could not say what he would have considered the truth had Wadley asked him in 1983 about his sexuality.
. After five years, Wadley destroys the donor source cards; Wadley microfilms copies only of the front of the card.
