What is a qualified expert who can testify as an expert in a medical malpractice case?

"A person is qualified to testify as an expert if he [or she] has special knowledge, skill, experience, training, or education sufficient to qualify him [or her] as an expert on the subject to which his [or her] testimony relates. Against the objection of a party, such special knowledge, skill, experience, training, or education must be shown before the witness may testify as an expert." (Evid. Code, 720, subd. (a).) The witness's qualifications "may be shown by any otherwise admissible evidence, including his [or her] own testimony." (Evid. Code, 720, subd. (b); People v. Fuiava (2012) 53 Cal.4th 622, 672.)