What is the test for qualified testimony in a medical malpractice case?

Under Evidence Code section 720, subdivision (a), 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 as an expert on the subject to which his testimony relates. [T]he determinative issue in each case must be whether the witness has sufficient skill or experience in the field so that his testimony would be likely to assist the jury in the search for the truth.... [Citation.] Where a witness has disclosed sufficient knowledge, the question of the degree of knowledge goes more to the weight of the evidence than its admissibility. [Citation.] (Mann v. Cracchiolo (1985) 38 Cal.3d 18, 38, 210 Cal.Rptr. 762, 694 P.2d 1134.)