The narrow issue presented here is the determination of whether appellee’s alleged medical malpractice cause of action against Dr. Thomas and Dr. Barnes was timely filed pursuant to R.C. 2305.11(A).1
R.C. 2305.11(A), in effect at the time of the commencement of the action, provided in pertinent part that: *133expiration of time contained in this division, is given to any person in a medical claim that an individual is presently considering bringing an action against that person relating to professional services provided to that individual, then an action by that individual against that person may be commenced at any time within one hundred, eighty days after that notice is given.” (Emphasis added.)
*132“An action for * * * malpractice against a physician * * * shall be brought within one year after the cause thereof accrued * * *.
“If a written notice, prior to the
*133This court in Oliver v. Kaiser Community Health Found. (1983), 5 Ohio St. 3d 111, 5 OBR 247, 449 N.E. 2d 438, in paragraph one of the syllabus, stated: “Under R.C. 2305.11(A), a cause of action for medical malpractice accrues and the statute of limitations commences to run when the patient discovers, or, in the exercise of reasonable care and diligence should have discovered, the resulting injury. * * *>>
In Hershberger v. Akron City Hosp. (1987), 34 Ohio St. 3d 1, 516 N.E. 2d 204, paragraph one of the syllabus, we established a three-prong test for determining the accrual date of “resulting injury” when applying the statute of limitations under R.C. 2305.11(A). In Hershberger, we held:
“* * * [T]he trial court must look to the facts of the particular case and make the following determinations: when the injured party became aware, or should have become aware, of the extent and seriousness of his condition; whether the injured party was aware, or should have been aware, that such condition was related to a specific professional medical service previously rendered him; and whether such condition would put a reasonable person on notice of need for further inquiry as to the cause of such condition. * * *” (Citations omitted.)
We recognize that this court had not yet decided Hershberger when the case at bar was decided by the trial court and the court of appeals. Thus, this case presents this court with an opportunity to apply and further interpret Hershberger.
Both sides in this action have asked us to further explain the meaning of “extent and seriousness of his condition” found in the first prong of Hershberger. Furthermore, various courts of appeals in this state have been wrestling with, or have dealt with, a possible definition, e.g., Brosse v. Cumming (Aug. 4, 1988), Cuyahoga App. No. 54165, unreported; Mikhail v. Lewandowski (July 15, 1988), Lucas App. No. L-87-347, unreported; Marrelli v. Donich (June 16, 1988), Cuyahoga App. No. 54069, unreported; Glinatsis v. Melby (June 15, 1988), Summit App. No. 13417, unreported.
Admittedly, “extent and seriousness” are not terms of art and, therefore, do not lend themselves to easily discernible definitions. Since the three prongs of Hershberger overlap considerably, we believe that the best manner in which to explain “extent and seriousness of his condition” is to combine the three prongs. Thus, we now hold that the “extent and seriousness of his condition” language of the test set forth in Hershberger v. Akron City Hosp. (1987), 34 Ohio St. 3d 1, 516 N.E. 2d 204, paragraph one of the syllabus, requires that there be an occurrence of a “cognizable event” which does or should lead the patient to believe that the condition of which the patient complains is related to a medical procedure, treatment or diagnosis previously rendered to the patient and where the cognizable event does or should place the patient on notice of the need to pursue his possible remedies.
Moreover, we do not believe that a patient must be aware of the full extent of the injury before there is a *134cognizable event. It is enough that some noteworthy event, the “cognizable event,”2 has occurred which does or should alert a reasonable person-patient that an improper medical procedure, treatment or diagnosis has taken place.
If a patient believes, because of harm she has suffered, that her treating medical professional has done something wrong, such a fact is sufficient to alert a plaintiff “ ‘* * * to the necessity for investigation and pursuit of her remedies. * * *’ ” Graham v. Hansen (1982), 128 Cal. App. 3d 965, 973, 180 Cal. Rptr. 604, 609.
Under the circumstances of the case before us, it could be argued that appellee was on notice of appellants’ alleged negligence from a Pap smear taken on October 12, 1982. This Pap smear was found to contain Class III cells. However, since a Class III Pap smear gives an inconclusive result of the existence of cancer, we hold that the October 12, 1982 Pap smear was not a “cognizable event” because it would not have alerted appellee that Dr. Barnes and Dr. Thomas had improperly diagnosed her if, in fact, any misdiagnosis did occur.
Rather, we find that the “cognizable event” was when appellee learned she had invasive cancer on November 5, 1982. This knowledge that her cancer had become more extensive after she had cancer in situ, did or should have led appellee to believe that the follow-up treatment of Dr. Barnes and Dr. Thomas, which only consisted of taking Pap smears, was negligently rendered. The diagnosis of invasive cancer did or should have put appellee on notice to pursue her possible remedies against Dr. Barnes and Dr. Thomas.
Thus, the application of the Hershberger three-prong test to this case mandates that the accrual date of appellee’s action in malpractice against both Dr. Barnes and Dr. Thomas was November 5, 1982. Pursuant to R.C. 2305.11(A), appellee should have brought the medical malpractice action or sent a letter of notification to both Dr. Thomas and Dr. Barnes by November 5, 1983.
While appellee sent a letter of notification to Dr. Thomas on September 29,1983, which was within the one-year statute of limitations, appellee did not notify Dr. Barnes until June 27, 1984 that appellee also considered that he was at fault. This latter notification was not within the one-year statute of limitations.
Thus, we reverse the judgment of the court of appeals with regard to Dr. Barnes and reinstate the trial court’s decision granting him summary judgment. The court of appeals’ decision denying Dr. Thomas summary judgment is affirmed and the cause is remanded to the trial court for further proceedings consistent with this opinion.
Judgment affirmed in part, reversed in part and cause remanded.
Moyer, C.J., Sweeney, Holmes, Wright and H. Brown, JJ., concur. Resnick, J., concurs in part and dissents in part.This court has found the four-year statute of repose set forth in R.C. 2305.11(B) unconstitutional in Mominee v. Scherbarth (1986), 28 Ohio St. 3d 270, 28 OBR 346, 503 N.E. 2d 717; Hardy v. VerMeulen (1987), 32 Ohio St. 3d 45, 512 N.E. 2d 626; and Gaines v. Preterm-Cleveland, Inc. (1987), 33 Ohio St. 3d 54, 514 N.E. 2d 709.
We recognize that the term “cognizable event” will be criticized as a malleable term. This is understandable, but unfortunate. By their very nature such terms are difficult to specifically define.