— William and Frances Reese brought this medical malpractice action against Dr. James E. Stroh, Jr., alleging that he negligently failed to treat Mr. Reese’s emphysema with a protein replacement therapy called Prolastin. The trial court excluded the Reeses’ expert medical witness’ opinion testimony regarding causation as lacking sufficient foundation to go to the jury. The Court of Appeals reversed, holding such testimony should be evaluated under the test set forth in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993). We affirm that reversal, though under an analysis considerably different from that of the Court of Appeals.
Facts
In 1984, William Reese, hereafter referred to as the Plaintiff, began seeing Dr. Stephen Aprill for treatment of asthma. One year later, Dr. Aprill referred the Plaintiff to Dr. Stroh because he believed that Plaintiff’s condition involved more than asthma. Dr. Stroh, hereafter referred to as the Defendant, is board certified in internal medicine and allergy and immunology. In spring 1985, the Defendant diagnosed the Plaintiff as having asthma, chronic obstruction pulmonary disease, and alpha-1-antitrypsin deficiency (AAT deficiency). AAT deficiency is a rare genetic disease characterized by low serum levels of AAT, a blood-borne protein which inhibits the destructive action of certain enzymes in the lung. In some patients with AAT deficiency, those uninhibited enzymes can destroy lung tissue, causing emphysema.
When the Defendant diagnosed the Plaintiff with AAT deficiency in 1985, AAT therapy, marketed under the name Prolastin, was not available. The Defendant prescribed bronchodilator medications, steroids, and antibiotics, and urged the Plaintiff to stop smoking and to avoid allergens and environmental irritants. The Defendant told the Plaintiff that his condition was not serious and that *303he could expect to lose lung capacity at a rate approximately one percent per year faster than the average person. Unfortunately, the Plaintiff lost lung capacity more rapidly than the Defendant predicted.
In November 1989, the Plaintiff learned that his brother also had been diagnosed with AAT deficiency and was to begin Prolastin therapy, which had been approved by the Food and Drug Administration (FDA) in 1987. Prolastin therapy consists of administering Prolastin (a preparation of purified human AAT) intravenously at regular intervals to maintain AAT levels in the blood above the AAT deficiency threshold. Prolastin therapy has proven valuable in treating other serum protein deficiencies such as hemophilia. The FDA approved Prolastin for treatment of AAT-deficient patients based on the knowledge that Prolastin raises the level of antitrypsin in the blood, but without statistical proof of its efficacy.1 Plaintiff and his wife called the Defendant to inquire about Prolastin therapy. The Defendant declined to prescribe Prolastin because he regarded it as an expensive therapy of unproven benefit, and because he thought Prolastin therapy posed possible risks for transmission of blood-borne infections. In March 1990, the Plaintiff began Prolastin therapy with his brother’s doctor.
In October 1990, Plaintiff and his wife filed this action against the Defendant, alleging that his failure to prescribe Prolastin resulted in a preventable worsening of Plaintiff’s lung function. More specifically, Plaintiff contended that the Defendant should have treated him with Prolastin between 1987, when Prolastin was approved by the FDA, and 1989, when Plaintiff’s lung capacity fell below the critical range for treatment. The Defendant subsequently filed a motion in limine to exclude the *304testimony of the Plaintiffs experts on causation. The basis of the motion was that the "[P]laintiffs experts lack the foundation to state with reasonable medical certainty that the 18 month delay in Prolastin treatment caused [the Defendant’s] current pulmonary condition . . . .” Clerk’s Papers at 70. The trial court reserved ruling on the motion until trial.
The Plaintiffs first expert witness was Dr. Robert J. Fallat, chief of the pulmonary division at California Pacific Medical Center in San Francisco. Dr. Fallat is board qualified in internal and pulmonary medicine and has done research on AAT deficiency since 1966. After examining him as to his qualifications and the nature of AAT deficiency, as well as his knowledge about and experience with Prolastin therapy, the Plaintiff sought to elicit testimony as to whether Dr. Fallat had "an opinion with a reasonable medical probability basis as to whether or not Prolastin is an effective treatment for Alpha-1 Antitrypsin Deficiency patient such as Mr. Reese.” Verbatim Report of Proceedings (VRP) at 70 (June 18, 1992). After sustaining a foundation objection to the opinion, the trial court allowed the Plaintiff to continue Dr. Fallat’s testimony outside the presence of the jury as an offer of proof.
On the basis of the information and studies supporting the FDA’s approval of Prolastin, his own clinical experience, and information regarding the Plaintiffs medical condition, Dr. Fallat concluded that, based upon reasonable medical probability, Prolastin therapy would be effective for the Plaintiff. Dr. Fallat also concluded that there "wouldn’t be a handful of pulmonologists in the country” who, given the Plaintiffs circumstances, would not prescribe Prolastin therapy, and that by failing to prescribe Prolastin, the Defendant had not acted as a reasonably prudent physician. VRP at 103 (June 18, 1992). Dr. Fallat also defended the FDA’s decision to approve the drug without statistical proof that it was effective in halting the progression of lung disease.
*305After hearing the offer of proof, the trial court held that Dr. Fallat’s opinion would be inadmissible because it found that Dr. Fallat did not have a statistically significant basis for his opinion as to the efficacy of Prolastin therapy in treating the Plaintiff’s malady. Although the trial court did not state it was applying the admissibility test set forth in Frye v. United States, 293 F. 1013, 34 A.L.R. 145 (D.C. Cir. 1923), its explanation for rejecting Dr. Fallat’s testimony indicates it found Prolastin therapy not to be generally accepted within the relevant scientific community. See Frye, 293 F. at 1014.
In light of the court’s ruling, the Plaintiff decided not to call his other expert witnesses, whose testimony would have been to the same effect. The Defendant then moved for a directed verdict, which the trial court granted on the basis that "[Plaintiffl could not prove proximate cause.” Clerk’s Papers at 874. The Plaintiff’s motion for reconsideration was denied, and he appealed the trial court’s evidentiary ruling.
Division One of the Court of Appeals reversed the trial court, holding that the Frye test does not apply to expert testimony in civil cases, and that even if it did, Dr. Fallat’s testimony was admissible because the methods he used to reach his conclusion were generally accepted in the scientific community. Reese v. Stroh, 74 Wn. App. 550, 555-56, 874 P.2d 200 (1994). In rejecting the Frye test, the Court of Appeals expressly adopted the approach taken in Daubert, 113 S. Ct. at 2786. Finding Dr. Fallat’s testimony admissible under the Daubert standard, the Court of Appeals reversed the directed verdict and remanded for trial. Reese, 74 Wn. App. at 566. We affirm the reversal and remand but reject the Court of Appeals’ reliance on Daubert as unnecessary.
Analysis
The admissibility of expert testimony in Washington is governed by ER 702, which provides as follows:
If scientific, technical, or other specialized knowledge will *306assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by-knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.
As reflected in recent Washington cases, the rule involves a two-step inquiry—whether the witness qualifies as an expert and whether the expert testimony would be helpful to the trier of fact. State v. Russell, 125 Wn.2d 24, 69, 882 P.2d 747 (1994), cert. denied, 115 S. Ct. 2004 (1995); State v. Kalakosky, 121 Wn.2d 525, 541, 852 P.2d 1064 (1993); State v. Cauthron, 120 Wn.2d 879, 890, 846 P.2d 502 (1993); see also 5A Karl B. Tegland, Washington Practice, Evidence § 288, at 380 (3d ed. 1989). The bases of an expert’s opinion are set forth in ER 703:
The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence.
When the admissibility of novel scientific evidence is at issue, Washington courts initially turn to the general acceptance test derived from Frye. The general acceptance standard serves as a shorthand method for judges in deciding whether novel scientific evidence, or evidence which is in the "twilight zone” between the "experimental and demonstrable stages,” has a valid scientific basis. See Cauthron, 120 Wn.2d at 887 (citing Frye, 293 F. at 1014). Once novel scientific evidence has been deemed admissible under Frye, the trial court must analyze whether that testimony is proper expert testimony under ER 702. Cauthron, 120 Wn.2d at 889-90.
In the recent Daubert decision, the United States Supreme Court rejected the Frye general acceptance standard for determining the admissibility of scientific evidence. The Court held that the Federal Rules of Evidence supersede Frye and that the text of Fed. R. Evid. 702 *307contains no "general acceptance” prerequisite. Daubert, 113 S. Ct. at 2794. The Supreme Court observed, however, that even for admission under the Rules of Evidence, "the trial judge must ensure that any and all scientific testimony or evidence admitted is not only relevant, but reliable.” Daubert, 113 S. Ct. at 2795. The Court then announced a new standard for admitting both novel and well-accepted scientific evidence: the evidence must pertain to "scientific knowledge”, defined as falsifiable scientific theory, capable of empirical testing. Daubert, 113 S. Ct. at 2795-97. Under Daubert, it is the trial judge’s task to decide "whether the reasoning or methodology underlying the testimony is scientifically valid . . . .” Daubert, 113 S. Ct. at 2796.2
The Court of Appeals need not have decided whether to substitute Daubert for Frye in civil cases because the Defendant here did not argue that the theory or the methodology involved in Prolastin therapy lacks acceptance in the scientific community. Indeed, Dr. Fallat’s uncontroverted testimony was that the FDA approved the use of Prolastin in treating AAT-deficient patients. Rather, the Defendant objected to Dr. Fallat’s expert causation opinion on the basis that there have been no statistically significant studies proving the efficacy of Prolastin therapy when used to treat AAT deficiency.
An expert opinion regarding application of an accepted theory or methodology to a particular medical condition does not implicate Frye. See State v. Ortiz, 119 Wn.2d 294, 831 P.2d 1060 (1992) (Frye inapplicable where testimony based not on novel scientific procedures but on practical experience and acquired knowledge). Admissibility of a causation opinion under these circumstances is weighed *308under the general reliability standards of ER 702 and ER 703. While we acknowledge the invitation to adopt the federal test for reliability under Fed. R. Evid. 702 as outlined in Daubert, we decline to do so in this case and find that the issues here are fully resolvable under this state’s evidence rules and the cases interpreting them.
Expert testimony is usually admitted under ER 702 if helpful to the jury’s understanding of a matter outside the competence of an ordinary layperson. See State v. Ciskie, 110 Wn.2d 263, 279, 751 P.2d 1165 (1988); Riggins v. Bechtel Power Corp., 44 Wn. App. 244, 254, 722 P.2d 819, review denied, 107 Wn.2d 1003 (1986). Medical malpractice cases are a prime example of cases where such testimony is needed. 5A Karl B. Tegland, Washington Practice, Evidence § 300, at 435 (3d ed. 1989).
Indeed, the general rule in Washington is that expert medical testimony on the issue of proximate cause is required in medical malpractice cases. McLaughlin v. Cooke, 112 Wn.2d 829, 837, 774 P.2d 1171 (1989); O’Donoghue v. Riggs, 73 Wn.2d 814, 824, 440 P.2d 823 (1968). As one commentator explains,
The requirement of expert testimony to prove causation is a sound and logical rule. . . . [J]urors and courts generally do not possess sufficient knowledge and training to determine whether a physician’s or surgeon’s actions actually caused plaintiff’s injury. The medical field is foreign to common experience. The expert medical witness domesticates this field for the trier of fact, and counsel must be aware of this situation to best serve his client....
Robert J. Rudock, Comment, Medical Malpractice—The Necessity of Expert Testimony and the Use of a General Physician as an Expert Witness in a Malpractice Action Against a Specialist, 10 Ohio N.U. L. Rev. 37, 47-48 (1983).
Here, Dr. Fallat’s status as an expert is not in dispute. Nor should it be disputed that his testimony would prove helpful to the trier of fact. Few lay persons are well versed in either Prolastin therapy or its use in combatting AAT *309deficiency. In so observing, however, it is equally important to observe that Dr. Fallat’s testimony is not likely to overwhelm the jury or prove so technical that the jury is unable to judge its reliability.
The reliance test of ER 703 differs somewhat from the helpfulness test of ER 702. See 5A Tegland § 296, at 138 (Supp. 1995). ER 703 relates to the factual basis for the expert’s opinion and the rule permits an opinion based on the expert’s first-hand knowledge or on information generally relied on in the field of expertise. While an expert may express an opinion based on statistics, such a basis is certainly not required. See 5A Tegland § 306, at 455.
We do not find that lack of statistical support fatal to Dr. Fallat’s causation opinion. Such support is required neither by ER 702, ER 703, nor by our case law. Rather, medical expert testimony must be based upon a "reasonable degree of medical certainty.” McLaughlin, 112 Wn.2d at 836 (citing State v. Crenshaw, 98 Wn.2d 789, 802 n.2, 659 P.2d 488 (1983)); see also 5A Tegland § 291, at 396. Evidence establishing proximate cause in medical malpractice cases must rise above speculation, conjecture, or mere possibility. See McLaughlin, 112 Wn.2d at 837; see also Coffman v. McFadden, 68 Wn.2d 954, 961, 416 P.2d 99 (1966).
We agree with the Court of Appeals that Dr. Fallat’s proposed testimony, based on the information known to the medical profession at the time of Plaintiffs treatment, "is the type of information jurors and their physicians rely on in their everyday lives to make decisions about health care. There is nothing mystical about it, and jurors are perfectly capable of determining what weight to give this kind of expert testimony.” Reese, 74 Wn. App. at 565. A jury can certainly evaluate the foundation for Dr. Fallat’s opinion that the failure to prescribe Prolastin therapy caused a preventable worsening of the Plaintiffs condition. Furthermore, the jury can evaluate the Defendant’s reasons for failing to apply Prolastin as well as the lack of substantial statistical support concerning the therapy’s efficacy.
*310We conclude here that Dr. Fallat was prepared to offer an opinion on causation with a reasonable degree of medical certainty, based on his extensive experience in treating AAT deficiency and his participation in and reliance on studies using Prolastin therapy. This is in conformity with the rules of evidence and our cases.
In general, the admission or refusal of evidence lies within the sound discretion of the trial court. Cauthron, 120 Wn.2d at 890; Oliver v. Pacific Northwest Bell, 106 Wn.2d 675, 684, 724 P.2d 1003 (1986). The trial court abused its discretion by applying the wrong legal standard to the evidence. See Fraser v. Beutel, 56 Wn. App. 725, 734, 785 P.2d 470 (discretion abused where reason for exclusion of evidence contrary to law), review denied, 114 Wn.2d 1025 (1990). We reverse and remand this case for a reassessment of the proposed testimony in conformity with this opinion.
Durham, C.J., Dolliver and Guy, JJ., and Andersen and Brachtenbach, JJ. Pro Tern., concur.
The FDA determined that proving the efficacy of Prolastin in treating emphysema would require a population study involving 600 people, would take three to five years to complete, and would be very expensive. Because of the difficulties posed by such a study, the FDA decided to release the drug for AAT-deficient patients because of studies concluding that Prolastin corrected AAT deficiency in the bloodstream.
The Supreme Court rejected the Frye test because Fed. R. Evid. 702 does not expressly contain a general acceptance requirement. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 2794, 125 L. Ed. 2d 469, 480 (1993). It is interesting to note, however, that the rule is also bereft of any language regarding "falsifiability” or capable of "empirical testing.” Daubert, 113 S. Ct. at 2797. We also note that even Daubert applies general acceptance as a factor to consider in evaluating reliability.