W. Va. Code § 55-7B-3 – Elements of proof.

(a) The following are necessary elements of proof that an injury or death resulted from the failure of a health care provider to follow the accepted standard of care:
1. (1) The health care provider failed to exercise that degree of care, skill and learning required or expected of a reasonable, prudent health care provider in the profession or class to which the health care provider belongs acting in the same or similar circumstances; and
2. (2) Such failure was a proximate cause of the injury or death.
(b) If the plaintiff proceeds on the "loss of chance" theory, i.e., that the health care provider's failure to follow the accepted standard of care deprived the patient of a chance of recovery or increased the risk of harm to the patient which was a substantial factor in bringing about the ultimate injury to the patient, the plaintiff must also prove, to a reasonable degree of medical probability, that following the accepted standard of care would have resulted in a greater than twenty-five percent chance that the patient would have had an improved recovery or would have survived.